In recent decades, the research of nano-structure devices  has experienced rapid growth. These materials have supreme electronic, thermal, optical and mechanical properties and have received widespread concern in different fields. It is worth noting that gate hysteresis behavior of field effect transistors can always be found in ambient conditions, which may influence the transmission appearance. Many researchers have put forward various views on this question. Here, we summarize and discuss the mechanisms behind hysteresis, different influencing factors and improvement methods which help decrease or eliminate unevenness and asymmetry. Low-dimensional carbon ) displays extraordinary properties and shows great potential in many fields ,2. Graph2/doping-Si substrates is shown in What should be noticed is that device instability is one of the great challenges in the application of low-dimensional materials . Hystere2 ), CYTOP (Polyperfluoro- butenylvinylether), PMMA (poly(methylmethacrylate)) , ParylenMaterial made in different ways exhibits different levels of sensitivity. In contrast to this kind of device, whose CNT was produced by drop-casting suspension, CNT fabricated by CVD shows more sensitivity to PMMA passivation in eliminating the gap and can obtain a hysteresis-free device within a certain gate range , which m2O3 could enlarge hysteresis; they can work as humidity sensors for a quick response within one second of a humidity change [In addition, not all encapsulation helps to reduce hysteresis width. For example, the formation of NaPSS(poly(sodium 4-styrenesulfonate)) and Aly change ,89. Usiny change  is anothDirac of typical deposition and passivation material we proposed in this paper is shown in Mainly, the encapsulation layer has two functions: draw water or remove electrostatic charge on the interface . The com2O3 as the encapsulation layer with a distinct process [2O3 encapsulation [2O molecules at the interface [2O3 at the defect sites of graphene [In the case of graphene, researchers have tried various passivation materials, whereas many researchers concentrate on using Al process . For grasulation  shows thsulation  and redunterface , which interface . Accordinterface ,56,92,93nterface ,21. This2O3 on top is the process called oxidization of the Al seed layer [2O3 after pulses of pretreatment with O3 and H2O is the method that reduces hysteresis by achieving sufficient surface saturation on graphene and promoting nucleation [Other processes are proposed to eliminate the residues and block the charge trapping. Depositing the Al seed layer with oxygen chamber and then depositing Aled layer . In thised layer ,96. Growcleation . Using dcleation . Encapsucleation .2O3 has a negative effect on suspended CNT characteristics. Al2O3 deposition causes larger hysteresis for CNT [2O adsorption on the large hydrophilic surface of Al2O3 [2O3 deposition layer and the suspended structure of the device used in the experiment.According to the experimental results, the deposition layer of Al for CNT , and thiof Al2O3  or changof Al2O3 . Apart fIn addition, because of enhancement of the substrate dielectric constant and the neutralization brought from the amine group, PEI (poly(ethylene imine)) with increasing concentration in methanol solvent has an enhanced screening effect and hence has a neutral Dirac point and almost zero hysteresis . While u2O3 in the formation of OH- groups and the water layer via H-bonding [It is worthy to note that small residual hysteresis still remains after passivation. According to the classification of fast charging and slow charging, the contribution of the chemical reaction reduces significantly from 58% to 30% due to the process of encapsulation, but the charge exchange at the interface still exists, which is responsible for the remaining hysteresis . Meanwhi-bonding .CNT-FET with passivation layer of OTS do not show gate hysteresis within certain measurement conditions. When giving a larger volt on gate, the hysteresis reappears in the opposite direction with a smaller value, which may be due to other mechanisms such as the residue charges in oxide being fixed, which could not be eliminated in this way . Devices2 can strongly be suppressed [2 [2 to graphene still remains [2 with anneal at high temperature in vacuum is effective to solve hysteresis problem after exposed to water in short time. However, in this way, scatter centers increase, hence carrier mobility reduces by 25% [Similarly, the deposition layer of HMDS functions as the hydrophobic layer and hysteretic behavior of graphene on HMDS primed SiOppressed , which iessed [2 ,45. HMDSessed [2 . In comp remains . Deposits by 25% . Compares by 25% .2 FETs [Because of the substrate flatness and improved bonding at the interface ,101, no 2 FETs ,102. How2 FETs .2 substrate with the aim of reducing the interface charge traps, and improving hysteresis and carrier mobility. Compared with unmodified devices, fluoropolymer modified devices show time-dependent stability and meet saturation at 4% in the first week instead of decreasing with time in ambient condition with relative humidity of 45% [2 (bottom gate) and h-BN (top gate) [Other polymers are also used in deposition which is useful in solving hysteric problem. CYTOP (Polyperfluorobutenylvinylether) is a kind of amorphous fluoropolymer used to modify the SiOy of 45% . Paryleny of 45% . Paryleny of 45% . Howeverop gate) .Choosing appropriate film as deposition layer is the key point in order to improve transport. Another question we should consider in electrical model is that deposition way changes the equivalent oxide thickness (EOT) of bottom gate devices . TherefoWhat the temporal evolution of devices is coating encapsulation layer on the top of device with deposition layer on bottom . Compare2 substrate, which helps solve this problem [It may also be more efficient to suppress hysteresis for graphene than using alternative substrates such as h-BN  or reoxi problem ; one suc problem ,107.Apart from deposition and passivation, changing dielectric contributes to alleviate this phenomenon. Polymer dielectrics  perform2–Si3N4–SiO2 (ONO) layer which has high breakdown voltage, slow defect density and high charge retention capability [3N4 and CNT is small, the effective dielectric constant of this layer is almost 3 which means that it is easy to inject and extract charges [2−TiO2−HfO2 layer as dielectric instead of SiO2 which desorbs water slower than SiO2 [2 (5 nm) as dielectric show hysteresis-free device under certain measurement [Dielectric layer called SiOpability  is also  charges . Anotherhan SiO2 . In thishan SiO2 . Top gatsurement .2, Al2O3 and Si3N4 are 14.3°, 27.9° and 42.9°, respectively. Considering the role water played in transmission, the Dirac point and hysteresis width of these dielectric devices have similar trends [The water contact angles of SiOr trends .2 and h-BN/graphene/BN shows high performance as suppressed hysteresis and p-doping [Top gate FET with the structure of h-BN/graphene/SiOp-doping . Surrounp-doping ,113,114.0.2Ti0.8)O3) instead of SiO2 reduces Coulomb scattering with increased screening effects and improved transport characteristics, but no experiments have directly proven improvement in the hysteresis characteristic [Employing a high-κ substrate such as single-crystal epitaxial PZT and ultrahigh vacuum (UHV) could make the process more efficient. RTA with a temperature of 250 °C and a duration of 10 min set as the most effective parameters is helpful to make device hysteresis free . PuttingHowever, it is worth noting that although annealing in vacuum can greatly improve hysteresis width; exposing the device to atmosphere again introduces the possibility to rebound the hysteresis .2SO4 + H2O2 solution as the presentation of chemical improvement makes a contribution to the removal of residual impurities (such as photoresist) at the substrate surface [It is commonly believed that organic contaminations and residuals influence performance . H2SO4 + surface ,121, esp2 Plasma is an effective physical method which proved to be able to change traps caused by photoresist particles on the electrodes and SiO2 substrate [Oubstrate ,68,122. ubstrate .For graphene, Ga ion irradiation has been certified as an effective way to degrade hysteresis by controlling the dose. When choosing the appropriate dwell time, most defects coalesced, resulting in a high tunneling barrier. Thus, the electron-trapping probability declined, and the hysteresis value degraded .Next, we introduce several new methods. For graphene, it is significant to avoid the contact with water and remove residues. Three categories as wet transfer, semi-dry transfer and dry transfer are proposed as main method in previous improvement. This is also appropriate to CNT FET. Apart from that, printing and self-alignment shadow mask are also the focus of attention. The comparison of hysteresis result by different methods are listed in the The dry transfer method applies to CNT, which is similar to graphene. It optimizes the fabrication steps by laminating CNT and substrate by annealing and vacuumizing .Printing as a new method is used to make hysteresis-free and flexible substrates by aerosol jet printing techniques or inverse gravure printing techniques, etc. ,122. ChaThe self-alignment shadow mask is a great candidate to deposit metal or the passivation layer. They have tapered contact geometry or suspended geometry so as to avoid charge traps or polar molecules caused by contact ,124. In 3+ help remove the extra Cu2+ dopant [We find that the process detail of separation and transferring is a key step in obtaining great performance devices. Therefore, we classify the treatments reported in previous papers into wet transfer, semi-dry transfer and dry transfer. The traditional transfer way is carried out by separating copper and graphene with the PMMA supporter by etchant solution or bubbles. Then, the film is transferred to the target substrate in water. Several researchers changed the transfer media from water to IPA and anneal in UHV at 300 °C; all these processes work as methods to remove the residual charges and change the interface bonding in order to improve transport performance, such as making the electrical curve symmetrical and reducing CNP difference ,103. Rep+ dopant . Transfe+ dopant . The dif+ dopant .2O3 deposition films is conductive to confirm the completeness and effectiveness of the transferred film [Dry transfer and direct transfer avoid the contacts of graphene with water at the interface; researchers retrieved the graphene layer through carrier and stamp which are retracted after heating and pressure, as depicted in red film . The estred film . The topred film . Apart fFinally, it is commonly believed that graphene grown through chemical methods, such as chemical vapor deposition, is more defective than mechanically exfoliated graphene, which causes more structural defects and results in hysteresis. Experiments have proven that it is possible to produce high-quality graphene, similar to exfoliated graphene, with careful control of the parameters in CVD growth with higher methane partial pressure . Catalyt2, WS2, etc.) that may not be beneficial to electronic transistors. In devices, hysteresis should be avoided or controlled. In traditional semiconductor device, hysteresis should be avoided or mitigated because of instabilities and non-uniformity introduced by hysteresis in integrated circuits. In contrast, controllable hysteretic behavior in 2D material FETs has great potentials for various applications, such as sensors and nonvolatile memory devices [Gate hysteresis is a common phenomenon which can be observed in low-dimensional material (such as CNT, graphene, GNR, MoS devices .In this paper, we summarize several mechanisms related to the formation of hysteresis at surface, interface and dielectric, factors correlated with device characteristics, environment and measurement and also improvements against certain causes. The mechanism difference between CNT and graphene originating from these characteristics, such as band structure, contact and dimension, are illustrated.For improvement, water molecules play a vital role at the surface and interface. Because of this, deposition and encapsulation could significantly remove hysteresis. It is worth noting that most of the deposition and encapsulation could not reach the aim of hysteresis-free devices, and sometimes water molecules can penetrate the cover layer, especially at higher temperature in ambient condition. In addition, because of the existence of the extra layer, the electrical field lines may deviate from the plane capacitor. This generates extra problems related to the model. Heating and annealing in a vacuum or in other gas ambient under controlled temperature is helpful to remove physisorbed and chemisorbed water molecules quickly and conveniently. However, it should be noted that the atmosphere gas molecules could also introduce hysteresis because of doping effects. It is clear that chemical and physical improvements reduce adsorbates such as photoresist. This kind of adsorbates could cause charge injection at the interface and it needs to be strictly controlled. A changing dielectric is one method to eliminate hysteresis induced by the oxide interface and bulk, which are related to tunneling at the interface and breakdown in the dielectric. Apart from that, many new processes such as dry transfer, semi-dry transfer etching copper, self-aligned fabrication method and jet print improve hysteresis to different degrees.Overall, many researchers have explored distinct methods to remove hysteresis caused by the interface and the surface; almost no one try to control the delaying width by solving problems caused by three parts simultaneously. Fabricating hysteresis-free or hysteresis-controlled devices with high quality and a large area is still a difficult problem we need to solve and confront.


We had previously found that resorcinol–formaldehyde (RF) resin powders prepared by the base-catalysed high-temperature hydrothermal method act as semiconductor photocatalysts for H2O2 generation. Herein, we report that RF resins prepared by the acid-catalysed high-temperature hydrothermal method (~523 K) using common acids at pH < 4 exhibit enhanced photocatalytic activity. The base- and acid-catalysed methods both produce methylene- and methine-bridged resins consisting of π-conjugated and π-stacked benzenoid–quinoid donor–acceptor resorcinol units. The acidic conditions result in the resins with a lower bandgap (1.7 eV) and higher conductivity because the lower-degree of crosslinking creates a strongly π-stacked architecture. The irradiation of the RF-acid resins with simulated sunlight in water with atmospheric-pressure O2 generates H2O2 at a solar-to-chemical conversion efficiency of 0.7%, which is the highest efficiency ever reported for powder catalysts used in artificial photosynthesis.The photocatalytic generation of hydrogen peroxide from water and dioxygen (H Low-bandgap polymers hold great potential for photocatalytic generation of hydrogen peroxide, but increasing catalytic activity remains challenging. Here, a solar-to-chemical conversion efficiency of 0.7 % is reached for a resorcinol-formaldehyde resin powder prepared via acid-catalyzed high-temperature hydrothermal synthesis. The photocatalytic splitting of water to generate H2/O23, the reduction of CO2 with water to CO or HCOOH5, and the reduction of N2 with water to NH37 have been studied as methods for producing solar fuels, with particulate suspensions being the simplest systems for implementing these methods, owing to their ease of scalability9. In recent years, hydrogen peroxide (H2O2) has attracted significant attention as a solar fuel because it is a transportable liquid, can be used to generate electricity with a membrane-free one-compartment fuel cell10, and can be readily produced from water and O2 by semiconductor photocatalysis under ambient conditions12. The photogenerated valence band holes (VB h+) are consumed by the oxidation of water (Eq. (–) are consumed by the two-electron reduction of O2  efficiency for the H2O2 generation on recently reported photocatalysts based on a graphitic carbon nitride (g-C3N4) are ~0.10% (g-C3N4/PDI: g-C3N4 doped with pyromellitic diimide)15, ~0.20% (g-C3N4/PDI loaded with reduced graphene oxide)16, ~0.26% (g-C3N4 reduced with NaBH4)17, and ~0.27% (g-C3N4/PDI loaded with reduced graphene oxide and boron nitride)18, respectively. This is because they (i) do not absorb long-wavelength light (λ > 500 nm), (ii) show low activity with respect to the oxidation of water  affords methylene-bridged RF resin powders comprising the benzenoid forms of resorcinol, which are π-conjugated with the quinoid forms of resorcinol via methine linkers  and efficiently promote water oxidation  resinsers Fig. . This crers Fig.  hybridis22. Both basic and acidic conditions result in methylene-bridged RF resins, albeit through different mechanisms:22 the base-catalysed reaction is triggered by the deprotonation of resorcinol  exhibit photocatalytic activity 1.5 times higher than that of RF-base resins, even though both types of resins are methylene-bridged resins containing π-conjugated and π-stacked D–A units. The RF-acid resins exhibit a lower bandgap (1.7 eV) and higher conductivity because their lower-degree of crosslinking leads to the creation of a strongly π-stacked D–A architecture owing to the higher structural flexibility. Further, the RF-acid resins produce H2O2 with an SCC efficiency of 0.7%, which is the highest ever for powder catalysts during artificial photosynthesis.The next challenge is increasing the activity of the resins. It is known that RF resins can also be prepared under acidic conditions, although all previously reported studies were performed at low temperatures (298–373 K)nol Fig. , whereasnol Fig. . Therefo23. Each of the respective acids was added to a pure water containing resorcinol and formaldehyde (mole ratio of 1/2). The pH of the solution was adjusted to ~3 by controlling the amount of the acid added, unless noted otherwise. The formed reddish solution was kept in an autoclave at the designated temperature [x (K)] for 24 h. The Soxhlet extraction of the solid using acetone and subsequent drying in vacuo afforded the RF-acid-x resin powder. As shown in Fig. 2-523 resin, which was prepared using oxalic acid (pH 3.0), is a red-black powder, whereas the RF-NH3-523 resin, which was prepared by the base-catalysed hydrothermal method (pH 7.8), is a red-orange powder23. Scanning electron microscopy (SEM) images of RF-(COOH)2-523  was much larger than that of the RF-NH3-523 particles (0.57 µm). N2 adsorption/desorption analysis of RF-(COOH)2-523 2-523 (1.02 m2 g–1) was much smaller than that of RF-NH3-523 (14.6 m2 g–1); this was in keeping with the particle sizes of the two resin powders. Moreover, as shown in Supplementary Fig. 2SO4, HNO3, and CH3COOH) also consisted of spherical particles with similar diameters (2.5–3.1 μm). These data indicated that, irrespective of the acid used, the acid-catalysed high-temperature hydrothermal method affords resins consisting of particles larger than those of RF-base resins.The RF-acid resins were synthesised under hydrothermal conditions523 Fig.  indicate523 Fig.  confirmeλ > 420 nm) of a pure water (30 mL) containing the resin (50 mg) in an O2 atmosphere (1 bar) at 298 K under magnetic stirring. A Xe lamp was used as the light source. Figure 2O2 generated on the different resins after 24 h of photoirradiation. The RF-NH3-523 resin23 produced ~60 μmol of H2O2 whereas the RF-acid-523 resins produced >79 μmol of H2O2, indicating that the RF-acid resins exhibited higher photocatalytic activity regardless of the acid used. The temperature during the hydrothermal process for resin synthesis must be high (523 K); it was observed that the activity of RF-(COOH)2-x decreased with a decrease in the hydrothermal temperature. Changing the resorcinol/formaldehyde ratio and pH of the solution during the synthesis also creates spherical resin particles  analysis. The spectra of both RF-NH3-523 and RF-(COOH)2-523 27. The resins exhibited a signal corresponding to the quinoid C=O carbon28 at 182 ppm (c) as well as a signal corresponding to the methine carbon29 at 126 ppm (f), with the areas being the same in both cases. This confirmed the formation of π-conjugated benzenoid–quinoid units 23. Thus, both resins contain similar numbers of D and A units.As shown in Figs. its Fig. . Table 1l–n) than aromatic carbons (d–i), with the proportion of the linker carbons in RF-(COOH)2-523 being lower than that in RF-NH3-523. Further, as can also be seen from Table 2-523 is 23.5%, which is much lower than that in RF-NH3-523 (31.2%). The ratio of the number of the linkers to the number of aromatic ring was determined to be ~2 for RF-(COOH)2-523 and ~3 for RF-NH3-523. The average number of linkers substituted in a single aromatic ring was ~3 for RF-(COOH)2-523 and ~4 for RF-NH3-523 because each linker bridges two aromatic rings. This indicated that, in the case of the RF-base resins , which could be assigned to π-stacked aromatics. Moreover, the peak of RF-(COOH)2-523 was shifted to higher angles with respect to those of RF-NH3-523. This indicated that the D–A distance in RF-(COOH)2-523 was smaller, even though both resins contained the similar numbers of D and A units  also showed peaks that were shifted to higher angles 2-523 has a positive slope  of RF-(COOH)2-523 as determined from its Tauc plot  while the top of its VB (+1.92 V versus RHE) is higher than that of RF-NH3-523 (+2.21 V). In addition, the CB and VB levels of RF-(COOH)2-523 are sufficient for the reduction of O2 39. The intensity in the case of RF-(COOH)2-523 was stronger than that of RF-NH3-523, indicating enhanced π-electron delocalisation in the former case. Moreover, the photoirradiation of the resin increased the intensity, suggesting that the photoexcited resin generated h+–e– pairs. The irradiation of RF-(COOH)2-523 with λ > 420 nm light or with monochromated 550-nm light on a fluorine tin oxide (FTO) electrode resulted in a stronger photocurrent than that seen in the case of RF-NH3-523  performed under visible-light  than that of RF-NH3-523, indicating that the increased conductivity of RF-(COOH)2-523 enhances migration of the CB e– photogenerated in the resin. These findings suggest that strongly π-stacked D–A systems  ultraviolet–visible (UV–vis) spectra of the resins Fig.  show abslot Fig. , inset wlot Fig. . The bot8 V, Eq.  showed aght Fig.  indicateems Fig.  result i2-423 and −473 resins were 69/31 and 62/38, respectively; thus, these resins contained fewer quinoid units than RF-(COOH)2-523 (51/49). Accordingly, the π-stacking-related diffraction peaks of these resins  for the synthesis of the RF-acid resins must be high, as lower temperatures decrease the photocatalytic activity of the resins Fig. . As showins Fig.  appearedons Fig.  and proding Fig. , resulti2O2 generation on RF-(COOH)2-523  of the resin was in keeping with its absorption spectrum, meaning that the bandgap photoexcitation leads to the H2O2 generation. The resin showed a larger ΦAQY value than that of RF-NH3-523 over the entire wavelength region, representing its broader, stronger light absorption and higher conductivity. The photoexcited resin catalyses the reduction of O2 through the CB e– 2-523 in water with NaIO3 as an electron accepter43 under Ar  curves of the resins 2-523 resin by the photogenerated h+–e– pairs.The action spectrum for H523 Fig.  indicateion (Eq. ). Furthe2-523 in water containing H2O2 and NaIO3 as an electron acceptor under Ar. The activity for oxidative decomposition of H2O2 by the VB h+ on the catalyst 2-523 is higher than that on RF-NH3-523, again confirming that the activity of the former was higher. It can also be observed that, in the early stage, the formation rate increases rapidly but eventually becomes constant after prolonged photoirradiation (~3 h), as is also the case for RF-NH3-52323. Accordingly, the SCC efficiency for H2O2 formation becomes almost constant at ~0.7%, which is higher than that of RF-NH3-523 (~0.5%). The high activity in the early stage is attributable to the fact that the formed VB h+ are consumed by the self-oxidation of the resin in addition to the oxidation of water. This was also observed in the case of the RF-base resins23. Supplementary Fig. 2  and methylene  carbons but increased the numbers of aldehyde (a) and ketone (b) carbons, indicating that the methylol and methylene parts of the resin are oxidised by the VB h+, as is also the case for the RF-base resins23. However, its benzenoid/quinoid ratio (51/49) did not change noticeably after the reaction (50/50). Moreover, the absorption spectrum and XRD pattern of the recovered resin were similar to those in the fresh state 46 and the highest value ever reported for photocatalytic water splitting using powder catalysts (~0.5%)47. Thus, the stable generation of H2O2 on the RF-acid resins under sunlight has significant potential for use in the production of a liquid solar fuel.The activities of the RF-acid resins were evaluated under illumination with AM1.5 G simulated sunlight (1 sun). 2 Fig. . As showate Fig.  and d. Sate Fig.  confirmeate Fig. , and a sate Fig. . These d2O2 in water in the presence of atmospheric-pressure O2 under sunlight irradiation. Further, synthesis at lower pH levels (<4) results in a lower-degree-crosslinked RF resins with a strongly π-stacked benzenoid–quinoid D–A architecture. This, in turn, results in highly conductive, lower bandgap (~1.7 eV) resins that efficiently promote water oxidation and O2 reduction under irradiation with near-infrared (λ < 720 nm) light. These RF-acid resins generate H2O2 with an SCC efficiency of more than 0.7%, which is the highest ever for artificial photosynthesis using powder photocatalysts. Further, these resins can be prepared through a simple hydrothermal reaction using inexpensive reagents . The results reported here may, therefore, contribute to the development of low-bandgap semiconducting polymers and highly active photocatalysts for H2O2 generation, which, in turn, may aid the production of liquid solar fuels.As stated above, we found that RF-acid resins prepared by the acid-catalysed hydrothermal synthesis method (~523 K) act as highly active semiconductors for the photocatalytic production of H2SO4, HNO3, (COOH)2, or CH3COOH) were prepared as follows. To being with, resorcinol  and formaldehyde  were added to water (40 mL) under stirring at room temperature. Next, the acid in question was added to the solution, and the pH of the solution was adjusted to ~3. The solution was then transferred to an autoclave (capacity: 100 mL) and heated for 24 h (heating rate: 7 K min−1), where the cooling operation of the autoclave was done by natural air cooling. The resultant product was subjected to Soxhlet extraction using acetone (12 h) and dried in vacuo at room temperature (12 h).The RF-acid-523 resins  being tested and water (30 mL) were added to a glass bottle , which was then sealed using a rubber cap. Next, O16:The SCC efficiency was determined using the following equation2O2 generation is 117 kJ mol–1  while t13C NMR23, ESR (X band), DR UV–Vis, XRD, and XPS analyses (Mg-Kα radiation)48 and SEM49 and TEM imaging50 were performed as per previously reported procedures. The electrochemical measurements were performed using 0.1 M Na2SO4 (pH 6.6) as the electrolyte and a Pt wire and an Ag/AgCl electrode as the counter and reference electrodes, respectively50. The working electrodes were prepared with FTO, carbon paper, or indium tin oxide23. The LSV measurements were performed in an O2- or Ar-saturated 0.5 M phosphate buffer solution (pH 7)51. All the potential values were expressed with respect to the RHE for ease of comparison of the data obtained at different pH values. This was done using the following equations52:DD/MAS/Supplementary InformationPeer Review File


In this paper, the effectiveness of ultra-low-energy ion implantation as a means of defect engineering in graphene was explored through the measurement of Scanning Kelvin Probe Microscopy (SKPM) and Raman spectroscopy, with boron (B) and helium (He) ions being implanted into monolayer graphene samples. We used electrostatic masks to create a doped and non-doped region in one single implantation step. For verification we measured the surface potential profile along the sample and proved the feasibility of lateral controllable doping. In another experiment, a voltage gradient was applied across the graphene layer in order to implant helium at different energies and thus perform an ion-energy-dependent investigation of the implantation damage of the graphene. For this purpose Raman measurements were performed, which show the different damage due to the various ion energies. Finally, ion implantation simulations were conducted to evaluate damage formation. As revolutionary materials with unique mechanical, thermal, and electrical properties, graphene and other 2D materials such as transition-metal dichalcogenides (TMDs) have been the subject of extensive research and development in various fields, from electronics to biomedicine. Some of the new applications include for example sensors for biomolecules and environmental contaminants ,2,3,4, sSimulations of He implantation in graphene were conducted to provide a better understanding of the processes involved. Here, the damage formation can also be investigated depending on the implantation energy and the used fluence.−8 mbar).The ion implanter ADONIS ,23 was u voltage . Thus, iTo achieve electrostatic masking, the deceleration unit described in  is used.2 and Ni were used as samples, which were obtained from Graphene Supermarket . B was implanted with fluences of Monolayer graphene on SiO2 was used, so that the SiO2 layer acts as an insulator and the voltage drops only through the graphene layer. The samples were also obtained from Graphene Supermarket. He ions were used for the implantation with a fluence of To create an energy gradient for studying the damage of graphene when implanted with different energies, 20 nm copper contacts were first applied by sputter deposition on both sides of the graphene. Then, a constant voltage source was used to apply a potential difference of 100 V. The ground contact on the graphene was set to 0 V with respect to the 30 kV anode of the source, so that the incoming ions have an energy between 100 eV–0 eV. The current flow through the graphene layer results in a linear potential gradient along the surface. As sample, monolayer graphene on SiOications . For the measurement of the surface potential (SKPM measurements) of the sample after implantation using the electro static mask, measurements were performed with an Atomic Force Microscope, type MFP-3D Origin+ from Oxford Instruments Asylum Research , in Scanning Kelvin Probe Microscopy (SKPM) non-contact constant height mode. Here the cantilever is held at a constant height above the specimen and the force on the cantilever is measured based on an applied voltage between the cantilever and the specimen. Subsequently, the value for each measurement was averaged over an area of 5 µm × 5 µm. Normal AFM measurements were not recorded separately and the selected resolution was sufficient for averaging of the surface potential but not for specific height analyses. The damage formation was determined using Raman spectrometry. Raman spectra were measured using a confocal Raman microscope  equipped with a 532 nm Nd:YAG laser. The laser was directed onto the sample surface through an objective , with the maximum laser power remaining below 1 mW in order to avoid laser-induced modification. All the measurements were obtained in ambient conditions, at room temperatur.2 and Ni), and observing a similar change of the surface potential, both in values and in general behavior, it can be concluded that this effect is due to the doping of the graphene and not to the effects of the substrate.The SKPM measurements, shown in In graphene ,28. A tygraphene . Similargraphene .2. The sublimation energy of 7.428 eV is used as the bulk binding energy (or surface binding energy) of carbon. This also corresponds to the vacancy formation energy of graphene [To obtain a more profound understanding of the processes during implantation, simulations were performed using IMINTDYN , a binargraphene . For Si,Since IMINITDYN does not simulate a lattice structure, but assumes the layers as amorphous, the graphene layer was adjusted slightly to take the hexagonal arrangement of the atoms into account. Because of the lattice structure there is the possibility that an ion flies through the middle of the carbon ring without colliding with an atom. Therefore, the first layer in the simulation consists of 2/3 C-atoms and 1/3 vacancies since two C-atoms and one empty center are to be assigned to one carbon ring. The density of the layer, with a layer spacing of 3.35 Å, was then increased to 0.4965 The He ion energies 20, 40, 60, 80 and 100 eV were simulated with fluences of both 2 dependency of the backscattering cross section, where E is the projectile energy, the high backscattering yield is reasonable in the ultra-low energy regime. The fact that more O than Si is incorporated into the graphene is due to the double O concentration in the substrate (SiO2) as well as to the lower mass of O. Therefore the backscattering in the second collision of the cascade is more probable.. For Si c and O (. For Si d it can We have shown that, by using electrostatic masks and potential differences, graphene can be doped with different fluences in only one implantation step. In addition, by adjusting the deflection voltage, the transition region between the doped and un-doped regions can be set. This is a great step towards the production of electronical graphene devices such as transistors using ion implantation. By being able to implant a sample at different energies at different surface positions, future measurements and investigations can be accelerated and eliminates unintended experimental variations in sample preparation as only one sample needs to be implanted instead of multiple.These methods can be transferred to other 2D materials such as TMDs and therefore can be helpful for a better investigation and manipulation of these materials. Further experiments to sharpen the transition zone are planned. The simulations carried out can confirm the findings from the experiments and are therefore a valuable tool for predicting the processes during ultra-low energy ion implantation of 2D materials.


Graphene synthesized via chemical vapor deposition (CVD) on copper foil appears promising for this purpose, but residues from the polymethyl methacrylate (PMMA) layer, used for the wet transfer of CVD graphene, drastically affect the electrical properties of graphene. Here, we demonstrate a scalable and green PMMA removal technique that yields high-mobility graphene on the most common technologically relevant silicon (Si) substrate. As the first step, the polarity of the PMMA was modified under deep-UV irradiation at λ = 254 nm, due to the formation of ketones and aldehydes of higher polarity, which simplifies hydrogen bonding in the step of its dissolution. Modification of PMMA polarity was confirmed by UV and FTIR spectrometry and contact angle measurements. Consecutive dissolution of DUV-exposed PMMA in an environmentally friendly, binary, high-polarity mixture of isopropyl alcohol/water  resulted in the rapid and complete removal of DUV-exposed polymers without the degradation of graphene properties, as low-energy exposure does not form free radicals, and thus the released graphene remained intact. The high quality of graphene after PMMA removal was confirmed by SEM, AFM, Raman spectrometry, and by contact and non-contact electrical conductivity measurements. The removal of PMMA from graphene was also performed via other common methods for comparison. The charge carrier mobility in graphene films was found to be up to 6900 cm In a free-standing graphene layer, the electron mobility can even reach 200,000 cm2/(V·s) at room temperature, the highest value ever known in pure semiconductors [3 to 104 cm2/(V·s), decreased to 2 × 102–2.5 × 103 cm2/(V·s) after the transfer and PMMA removal in acetone [Graphene is a unique material with distinctive characteristics that has shown great potential for a wide range of applications, particularly involving its electronic structure and transport properties ,2,3. Thenductors ,6. Unfornductors , and thanductors ,9,10. Tonductors ,12. Thisnductors ,15,16,17nductors ,19. Aftenductors . It has nductors  that thenductors , even stnductors , acetic nductors , chlorobnductors , and chlnductors . Graphennductors ,27,28,29 acetone . Therefo3–4 × 103 cm2/(V∙s), which until now was the upper limit of the devices fabricated of CVD-grown graphene [Various strategies have been proposed to ensure effective PMMA removal after graphene transfer and preservation of the unique properties of graphene by maintaining its structural integrity ,32,33. Ographene .p-doping into graphene, changing its electrical properties in an undesirable way.In order to ensure the stability of graphene’s chemical composition and structure, and achieve reasonable mobility, scientists have turned attention to the degradation of the polymer under relatively mild processing conditions . As earlOn the other hand, regarding the quality of graphene detected after the removal of PMMA, an aqueous solution of isopropyl alcohol (IPA) looks promising as a solvent, since by its nature it does not introduce additional residuals that dope graphene, as it can be seen after using other solvents for PMMA removal . The aquIn this work, we propose a new approach for the efficient removal of the DUV-exposed PMMA from the surface of wet transferred CVD graphene. Traditionally, the removal of the PMMA film during wet transferring of the CVD graphene implies the dissolution of the polymer (a chain of compounds of the ester type) or the MMA monomer, after thermal or radiational decomposition, with solvents such as acetone (refers to the type of ketones). We propose here to modify this scheme by dissolving the DUV-exposed PMMA with a binary polar solvent of isopropyl alcohol and water. We show that complete dissolution of PMMA is achieved on CVD graphene. As far as we know, the investigation of modification in the polarity of the PMMA under the action of DUV ,47,48 as2 substrates of 1 mm thickness . To expose PMMA to DUV we have employed commercial crosslinker  equipped with 254 nm illumination source (UVC Philips TUV T5 lamps), with exposure time of 8 h at the distance between a source and a sample of 16 cm. To characterize the change in the polarity of the exposed PMMA, the optical contact angle meter  was used to assess the degree of hydrophilicity of the surface.To investigate the effects of DUV exposure on PMMA, 996 K molar mass PMMA  layers were prepared by spin coating a 4% PMMA solution (0.53 g/10 mL) in anisole  to the desired substrate and drying at 180 °C resulting in PMMA film of about 250 nm. For various experimental investigations we have used different substrates. The pristine and DUV-exposed PMMA samples were prepared on a 2 mm-thick fused silica substrates  for the investigation of absorbance spectra in UV spectrum range using a UV/VIS spectrometer  in the transmission geometry. Changes in IR absorbance in PMMA after DUV exposure were investigated using the FTIR spectrometer  in the transmission geometry with 1 mm aperture in a vacuum environment with PMMA samples on CaF−1. For each sample, 10 spectra were recorded with an integration time of 60 s and used for statistical analysis. The electrical characteristics of graphene were investigated using contactless optical and contact methods. For optical contactless characterization, terahertz time-domain spectroscopy (THz-TDS) was performed with the commercial THz-TDS spectrometer  in the transmission geometry of a focused beam with a spot size around 2–3 mm. Since THz-TDS measurements only provide information about the conductance of the graphene sheet, contact Hall measurements in a 0.5 T magnetic field  were also carried out to gain insight into the doping type of the samples.Finally, sets of graphene samples were prepared for a proof-of-concept of the proposed approach by taking a commercial monolayer CVD graphene synthesized on a copper foil with protective PMMA coating  and transferring it on float zone high resistivity (HR) (>10 kΩ∙cm) silicon wafers . The IPA , acetone  and chloroform  were used as solvents. The quality of the prepared graphene samples was determined by optical microscopy, SEM, atomic force microscopy (AFM), Raman spectroscopy, THz time-domain spectroscopy (TDS), and Hall effect measurements. Scanning electron microscopy images were obtained using secondary electrons at 2 kV and 25 pA beam current in a dual-beam system . The conductive microscopy was performed using scanning probe microscope system . Sample bias was set to value of 20 mV using tunneling AFM (TUNA) module under ambient conditions. For these measurements the PtIr cantilever, 300 um length and 0.8 N/m spring constant (type RMN-12PT300B) was used. The samples were characterized by a Raman spectrometer  using a 1800 lines/mm grating, a microscope equipped with a 50×/0.8 NA objective, and a continuous-wave 532 nm excitation laser operating at a power of 0.6 mW. The beam was focused to the size of a spot with a diameter of 0.8 μm on the sample surface. The position of the Raman spectrum bands on the wavenumber axis was calibrated by a silicon peak at 520.7 cmOne of the main points of the proposed method is the change in the properties of PMMA, both chemical and physical, when the polymer is exposed to UV radiation. We show that deep-UV irradiation with a wavelength of 254 nm, used for this purpose, leads not only to photodegradation of the polymer due to the main-chain scissions, as occurs with more powerful irradiation sources, but also the appearance of new species, the formation of which is more pronounced in the case of photodegradation at 254 nm.Since DUV exposure of PMMA takes longer due to the lower energy of irradiation, some products formed after main-chain scissions further absorb UV photons and contribute to the degradation of the polymer by side-chain scissions that are occurring in parallel with the main-chain scissions. As a result, new chemical species are formed, including ketone-type and aldehyde-type carbonyl compounds . To conf3 and CH2 groups , C=O stretching (1729 cm−1), and stretching vibration of the C−O−C group (1148 and 1193 cm−1). The vibrational spectrum of PMMA has been analyzed in detail in previous publications [–1), the relative intensity of the 1148 cm−1 band associated with the symmetric stretching vibration of the C−O−C group decreases the most, indicating DUV-radiation-induced cleavage of ester bonds. The negative-going feature at 1729 cm–1 due to the C=O stretching vibration of the ester group confirms this scenario. In the C−H stretching vibration spectral region, one can find direct evidence of radiation-induced destruction of CH2 groups, as two intense negative-going bands at 2851 and 2919 cm−1, associated with symmetric and asymmetric stretching vibrations of the methylene group, respectively, appear in the difference spectrum. In addition, the negative-going band, due to CH2 scissoring deformation vibration, is visible near 1486 cm–1. These spectral changes indicate cleavage in the vicinity of the –CH2−moiety (main chain). The positive-going feature near 1710 cm−1 reveals the DUV-exposure-induced formation of new species, most likely containing C=O of aldehyde and/or ketone functional groups. The positive-going broad feature near 1618 cm−1 is consistent with the formation of sp2-hybridized carbon bonds, aromatic carboxyl groups, and hydroxyl groups [−1 support the formation of compounds containing C−O bonds or/and hydroxyl groups. Earlier works investigating similar FTIR spectra of DUV-exposed PMMA also concluded that bands of newly produced species were observed in the IR spectrum, and were attributed to ketone-type and aldehyde-type compounds [To gain insight into the molecular changes of DUV exposure induced in PMMA film, we performed an analysis of FTIR transmission spectra . The domications ,72,73,74ompounds .Chemical changes in the exposed PMMA structure are manifested in the modification of the physical properties of the final products after the photochemical reaction, specifically in polarity. Namely, the increase in polarity is the first basis of the improved solubility mechanism of PMMA exposed to DUV. After exposure, the newly produced ketone and aldehyde type compounds with a polarity higher than that of the original ester functional group can form H-bonds more efficiently, when acting as an acceptor, namely a carbonyl oxygen acceptor, upon subsequent dissolution.Assessing the polarity of the material is not an easy task, but the water contact angle has been proven to be directly linked to the polarity of the surface . Contact3H6O 0.355), chloroform (CHCl3 0.259), anisole (C7H8O 0.198), or toluene (C7H8 0.099). However, it is known that PMMA is practically insoluble in water at ambient temperature [Since higher polarity products form hydrogen bonds, which are much easier than those of pristine PMMA upon subsequent dissolution, it is expected that this will result in the improved removal of PMMA when using a solvent of suitably high polarity. One could expect that the most effective dissolution will be achieved when the solvent with the highest polarity is used, namely, water (relative polarity 0.998) instead of solvents historically used for this purpose such as acetone  were studied via SEM and AFM. SEM images of graphene films prepared by different PMMA removal methods are shown in To compare the discussed method of PMMA removal, additional PMMA/graphene samples were prepared using the same wet transfer process (steps 1–3), but with PMMA removed with common solvents: acetone and chloroform. A total of five samples were prepared: three samples with DUV treatment and development in aqueous IPA (samples DUV1–DUV3), and one sample each for PMMA removal for 18 h at 23 °C with acetone and chloroform, respectively. As a reference, the standard commercially transferred graphene film to SiO−1 (G peak) and 2674 cm−1 (2D peak). It is worth noting that the D peak at around 1350 cm−1 falls into elevated background, and was not included in the analysis. To obtain the precise position and FWHM of G and 2D lines, a Lorentz function was used to fit each peak obtaining the mean and standard deviation values of peak intensity and FWHM. The results for all the samples are provided in −1, respectively. The samples prepared using chloroform and acetone exhibited a high 2D/G intensity ratio (>2.4), but their FWHM was larger in comparison with DUV samples, namely, FWHM ≥ 30 cm−1. To consider the repeatability of our process in the fabrication of DUV samples, we fabricated three DUV samples over two separate processing runs, the results of which are listed in the −1. Additionally, the fitted positions of the 2D and G lines are used in correlational position analysis, between the 2D and G peaks, which makes it possible to investigate strain and doping in graphene films [0; 2D0) of free-standing undoped graphene is marked with a large black cross, the position of which is at 1581, 2671 cm−1. The distribution of positions extends to a line in undoped graphene under biaxial strain, and is plotted as a black line, which is the usual case for graphene transferred onto Si [p-doped and under biaxial strain, this will cause the G peak position to move towards higher Raman shifts and parallel to the strain line. Since the data of the samples prepared in this study  are distributed between the theoretical lines of undoped graphene and 5 × 1012 cm−2 doping, this shows a low doping of the prepared graphene samples. A different behavior is observed for a commercially transferred graphene sample. A significant shift in the data points indicates a high doping of graphene films, which was found to be close to 2 × 1013 cm−2, demonstrating a low sheet resistance of the graphene according to the manufacturer data sheet.The Raman spectra for the selected sample DUV3 are shown in ne films . The resAny future applications of CVD graphene require contactless methods of graphene film electrical properties that can conduct large-area mapping and function rapidly . One of kness dS ,85,87. TS, sheet carrier density  NS, and carrier mobility µ, were found from fitting results using the respective definitions:Relevant electrical properties of the graphene films, such as sheet resistance R12 cm−2 and mobilities higher than 2410 cm2/(V·s). The best overall result was achieved for sample DUV3, which demonstrated very low residual doping and very high mobility values, found to be at the level of 0.8 × 1012 cm−2 and 6900 cm2/(V·s), respectively.The results for all samples are summarized in p-type conductivity (DUV1 and DUV2), while the last one demonstrated n-type conductivity (DUV3). Samples prepared using chloroform and acetone solvents showed n and p-type conductivity, respectively. The varying conductivity type for the DUV samples could be a result of slight unintentional doping during PMMA removal, since for all the samples analyzed, carrier density was below 2.5 × 1012 cm−2. These results indicate that DUV-assisted PMMA removal in an IPA/water solution makes it possible to obtain clean CVD graphene with high charge carrier mobility values, which are required in the field of high-frequency electronics.Remote THz characterization is a powerful tool; however, it does not provide information on the type of free-charge carriers that interact with THz radiation. To gain more insight into this, we added Ag epoxy contacts to each corner of the rectangular graphene samples and performed Hall experiments. Two of the three samples prepared using DUV treatment exhibited In conclusion, a green and cost-efficient method has been developed for PMMA supportive layer removal from the surface of CVD graphene wet transferred onto an application-compatible substrate of choice, which allows one to obtain scalable graphene with high electron mobility for the needs of high-frequency graphene-based electronics and optoelectronics. In terms of the method, we propose to first modify the polarity properties of PMMA via exposure to deep-ultraviolet (DUV) radiation with a wavelength 254 nm, so that not only the decomposition of PMMA polymer to MMA monomer occurs, as typically happens after thermal or photo-irradiation, but also the formation of final products  with polarities higher than those of the initial products (esters). Such products form hydrogen bonds much more easily upon subsequent dissolution, which would allow for better removal of PMMA using a solvent of high polarity. We propose to use a binary solvent mixture of isopropyl alcohol and water, which is not only extremely polar, but is also a more environmentally friendly solvent. Generally, an aqueous alcohol—such as ethanol—can be used, especially since it has no environmental impact at all. Another advantage of the method is that low-energy irradiation does not form free radicals, thus the released graphene remains intact, unlike in higher-energy PMMA decomposition methods, such as with an electron beam or even DUV at 195 nm.2/(V·s), which makes the proposed method suitable for removing PMMA from the graphene surface in the industry of high-performance large-scale electronic devices based on graphene.The high quality of graphene after the removal of PMMA using our method was confirmed with SEM, AFM, and Raman spectrometry. Electrical transport properties of released graphene, which are of special interest to current research, were fulfilled by means of contactless optical (THz-TDS) and contact  techniques. It was found that the mobility of charge carriers in graphene films reaches up to 6900 cmN.A. and I.K. are inventors on a provision patent application filed by the Valstybinis mokslinių tyrimų institutas Fizinių ir technologijos mokslų centras .


Larrea tridentata (gobernadora) and Capsicum Chinense (habanero). Graphene oxide was synthesized by the modified Hummers’ method and subsequently reduced using natural extracts to obtain a stable and environmentally friendly graphene precursor. Consequently, the gobernadora aqueous extract was found to have a better reducing power than the habanero aqueous extract. This opportunity for green synthesis allows the application of RGO in photocatalysis for the degradation of the methylene blue dye. Degradation efficiencies of 60% and 90% were obtained with these materials.In the present work, reduced graphene oxide was obtained by green synthesis, using extracts of  Nowadays, as a consequence of industrialization, the world faces problems with air, soil, and water pollution. This problem is becoming increasingly important despite the existence of pollutant removal treatments and waste reduction and disposal programs. In many of these processes, the problem is only partially eliminated, so pollution of rivers and seas is increasing, and the damage this is causing is of an unimaginable magnitude. In the last two decades, the organic pollutants discarded by industries have no control, which has led to water pollution being severely affected. The World Bank estimates that 17–20% of industrial water pollution comes from textile dyeing. Wastewater from textile industries is a major problem for conventional treatment plants worldwide. The release of these wastewaters into natural environments is very problematic for aquatic organisms. The wastewater generated by the textile industries is known to contain considerable quantities of non-fixed dyes, especially azo dyes, and a large number of inorganic salts. It has been estimated that more than 10% of the total dye is used in dyeing processes while the rest is released to the environment. Therefore, it is necessary to study new processes that allow the efficient elimination of pollutants, which are affecting the environment so much ,4.2 ..Larrea TCapsicum Chinense (habanero pepper) is an herbaceous plant with a high source of phytochemicals or bioactive compounds that have shown benefits to human health. The main compounds of Capsicum Chinense are phenolic compounds, capsaicinoids, flavonoids, vitamin C, carotenoids and tocopherols. The capsaicinoids present in the chili fruits of the genus Capsicum Chinense have various functional properties such as: antioxidant, anti-inflammatory, antimicrobial and antitumor capacity, among others. Additionally, natural capsaicin with a high level of purity is of great economic importance and appreciated in the pharmaceutical, food and chemical industries  natural extract—deionized water. The behavior of the extract concentration and it is reducing power in graphene oxide was analyzed.To prepare the gobernadora extract, 30 g of v/v). Subsequently, the solutions were heated at 80 °C for 12 h under constant agitation in a reflux system. After 2 h of heating, the color began to gradually change from brown to black, indicating the start of graphene oxide reduction. After the reduction was complete, the color turned dark black and this indicated the reduction of graphene oxide and the formation of reduced graphene oxide (RGO). To complete the green synthesis, the mixtures were centrifuged and washed with deionized water several times and finally dried at 60 °C for further characterization.Once the aqueous extracts were prepared, the graphene oxide solutions were exfoliated and mixtures of the aqueous extract solutions with GO were prepared in a ratio of 4:1 (% 0) of the solutions was noted before photodegradation. Dye degradation was carried out sequentially by individual dye solutions of MB.For the photocatalytic degradation study, dye selected was methylene blue (MB). UV light (365 nm) irradiation was applied to find out a suitable as well as effective way to eliminate the maximum percentage of dye. For photodegradation, the dye solution was prepared in deionized water at the concentration of 10 mg/L. Further, 20 mg/L of RGO is added to the prepared dye solution. After, these mixtures were subject to low shaking for 20 h under dark conditions for the adsorption and desorption of dye molecules onto the surface of RGO. At the end of the dark exposure period, each mixture was subjected to UV–Vis spectrophotometer analysis and the initial concentration . Dye degradation could be calculated from the absorbance values using the following formula ,31,32,33−1. To determine each of the carbon members, Raman spectroscopy using the LabRam VIS-633 equipment was used. The measurements were made in the spectral range between the wave numbers 1000 and 3500 cm−1. Finally, the morphology of our material was determined using a transmission electron microscope with a filament of lanthanum hexaboride at a scale of 100 and 200 nm.The XRD technique allows monitoring the oxidation process of graphite. The diffraction patterns of the GO and RGO were performed in a Miniflex II model, Rigaku brand diffractometer (λ = 1.5418), the measurements of the samples were made in a 2Θ range of 5 to 70°. To determine the reduction of graphene oxide the following techniques were used: UV–Vis, FT-IR and Raman. The interaction of the samples with the electromagnetic radiation was determined by UV–V is spectroscopy with a Perkin Elmer spectrophotometer, scanning wavelengths from 248 to 400 nm, the measurements were made in quartz cells of a 1 cm optical path over aqueous suspensions of graphene The presence of the characteristic bonds as well as the loss of oxygenated groups was determined by means of the FT-IR spectra of the samples with a Perkin Elmer Paragon 1000 spectrometer, the measurements were made in the spectral range between the wave numbers 500 and 4000 cmIn this work, six samples of a colloidal suspension of graphene oxide (GO) were reduced with different natural aqueous extracts (habanero and gobernadora). UV–VIS allowed the determination of whether suspensions contained transient products of GO and if it had been partially reduced (RGO) as the natural extract concentrations increased. In this technique only five samples were analyzed: (a) GO, (b) HAB1, (c) HAB2 (d) HAB3, (c) GOB1, (f) GOB2 and (g) GOB3.Larrea Tridentata extract is a better candidate as a GO-reducing agent compared to Capsicum Chinense extract [During the oxidation of graphite, oxygen adheres to the graphene layers, thus increasing the polarity of the layers which in turn increases its solubility in water. This results in a change in the color of the solution from yellow to brown. depending on the GO concentration, the brown color can be of different intensities. The GO that is formed has an absorption maximum at 225 nm for a well-oxidized material . TheUV–V extract ,36,37,38The reduction of the GO leads to the loss of oxygenated functional groups, so it was decided to apply FT-IR spectroscopy to verify if there are differences between the amount and type of functional groups in the samples. The analyzed FT-IR spectra are presented in −1 and was attributed to the C-OH stretch bands of the hydroxyl group. The second peak of less intensity was located at approximately 1620 cm−1 and was attributed to the skeletal vibration C=C. A third peak was located at approximately 1050 cm−1 and was attributed to the C-O alkoxy stretching vibration. Finally, a peak of very low intensity of approximately 1730 cm−1 was attributed to the vibration of the carbonyl group C=O [−1 and was attributed to the stretching vibration of the epoxy group C–O–C [−1 and was attributed to the skeletal vibration C=C of the graphene planes [−1, was attributed to the stretching vibrations C–OH of a hydroxyl group [2 carbon bonds, as seen by the increase in the band at 1620 cm−1, corresponding to the C=C links. In addition, in all the samples a two-diminution of intensity was observed in the peaks of the functional groups C–O–C and C–OH [Of all the FT-IR transmittance spectra of the samples analyzed, peaks attributed to the oxidation of graphite and graphene oxide can be observed See . Oxidizeroup C=O ,38,39. Tup C–O–C . The nexe planes ,42. A thyl group ,44,45. Tand C–OH ,38,39  and the D-peak (~1355 cm−1) arising from the mode of respiration of photons of the K symmetry point A1g [Raman spectroscopy is considered a popular technique for characterizing the structural and electronic properties of graphene, including disordered and defective structures, defective density and doping levels. Raman spectroscopy is very sensitive to structure for the characterization of carbon-based materials, especially C=C double bonds that lead to high-Raman intensities. The Raman spectrum of graphene is generally characterized by two main characteristics: the G-peak, which arises from the first-order dispersion of the Eoint A1g ,38,43.−1 while the D-band appeared in the range of 1342–1350 cm−1. Interestingly, the Raman spectrum of GO after reduction with natural extracts had higher intensities than GO, these high intensities could indicate the introduction of sp3 defects after functionalization and incomplete recovery of the graphene structure. The variation of the relative intensities of the G-band and the D-band in the GO Raman spectra during the reduction generally reveals the state change of the electronic conjugation. In this work an increase in the number of sp2 domains was indicated after GO reduction [Our results  show thaeduction ,20,44  GOB3 RGO-Larrea 20%.On the other hand, it is well known that the Raman dispersion of two phonons (2D) of graphene-based materials is a valuable band for differentiating monolayer graphene from double layer or multilayer graphene, since it is highly perceptive to the stacking of graphene layers. Usually, a Lorentzian peak is observed for the 2D band of the monolayer graphene sheets at 2697 cmayer RGO ,46. FiguD/IG) and will be used to compare the way in which the structural disorder grows in the graphitic network. The locations of both D- and G-bands and the ratio between their intensities are consistent with the characteristic values reported elsewhere. When pristine graphite was oxidized to GrO, the ID/IG ratio of the resulting material significantly increased indicating a higher level of structural disorder and a larger number of defects in the graphene layers due to the oxidation process. After sonication to obtain GO, ID/IG relationship in the resulting material slightly increased, indicating that the exfoliation process also incorporated further defects into the structure. Logically, the distance between defects (determined as 2) decreased from graphite to both GrO and GO [O and GO ,49,50,51The XRD technique allows for controlling the oxidation process of graphite. The data reported in the literature show that graphite has a reflection peak at approximately 2ϴ = 26°, which corresponds to a spacing d of 0.335. Upon oxidizing graphite, the reflection peak (002) changes to the angle 2ϴ = 10° (space d = 0.906). This increase in the d-space is largely due to the intercalation of water molecules and the formation of functional oxygen-containing groups in the graphite layers ,51,52. OThis characterization technique was used to observe the morphology and size of layers of graphene or graphene oxide, as well as their sizes and imperfections. The samples were prepared by dispersion in alcohol and then sonicated for 10 h. A drop of the suspension was deposited on to a copper grid to analyze it. 16H18N3Cl1S1 and a molecular weight of 319.85 g/mol. Its maximum absorbance is at 663 nm [Methylene blue (MB), also called methylthionine chloride, is an organic dye with the molecular formulation Ct 663 nm . The abso) with the absorbance values obtained at specific time intervals (Ct) (The degradation efficiency (%) was calculated from the absorbance values obtained for the initial dye concentration  .The first step of the photocatalysis is the activation of the photocatalyst by the reconstruction of the photocatalyst surface via electromagnetic radiation illumination. The electromagnetic radiations interact with the surface plasmons of the photocatalyst and excite the electrons into the higher states. Upon the excitation of the negatively charged electron (e−), the positively charged hole (h+) is created in its place. These e−/h+ pairs are responsible for the photocatalytic capability of the photocatalyst. These generated e−/h+ can undergo recombination reactions via relaxation processes which lead to the deactivation of the photocatalyst ,56,57.From the sample of RGO with gobernadora extract a, it is The efficiency of photocatalytic degradation of MB with a photocatalyst was calculated from absorbance values and is presented in The previously studied reduced graphene was compared with other studies on the removal of MB dye from similar light sources . Numerouv/v), the better the reduction of GO. Using Raman spectroscopy, we noticed that both GO and RGO obtained had a multilayer structure, possibly due to the lack of exfoliation time in the ultrasound period before and after the graphene oxide reduction. Prior to characterization by TEM microscopy, RGO was exfoliated for 10 h and monolayers were obtained. The TEM images reaffirmed the multilayer structure in RGO samples prepared by our eco-friendly route of synthesis.Based on these results, we obtained that the concentrations of the extract directly affect the reduction of our material, so we conclude that the higher the concentration of the natural extract  and Capsicum Chinense (habanero). We believe that the reduction is largely due to natural-reducing agents such as ascorbic acid, carotenes, polyphenols and capsicum contained in plants. In addition, we can also say that the Larrea Tridentata extract acts as the best GO reducer, according to the results obtained from the FT-IR, UV–Vis and XRD characterization techniques. On the other hand, it was possible to verify that the RGO reduced with natural extracts can act as a photocatalyst for the degradation of MB dye [Reduced graphene oxide (RGO) was obtained through an eco-friendly synthesis applying a green chemistry methodology and using natural extracts of f MB dye ,69,70,71The use of eco-friendly reducing agents to synthesize graphene garners great interest thanks to the great potential of applications that they can have. It is considered as one of the most versatile methods. These kinds of reagents are shown to be an alternative to inorganic compounds, such as hydrazine or other non-biocompatible or toxics reducing agents, as well as with better catalytic properties compared to other organic reducers, such as glucose. They are also safe to handle and the reaction co-products are biocompatible.


Although sarcoidosis is an established cause of multiorgan dysfunction, acute presentation with thrombotic microangiopathy resulting in severe renal and hematological sequelae has not been reported. We describe the case of a patient presenting with hypercalcemia, pancreatitis, and acute renal failure, followed by microangiopathic hemolytic anemia. Although there were no significant respiratory symptoms, thoracic radiology and mediastinal lymph node biopsy results were in keeping with sarcoidosis as the underlying cause of this multisystem presentation. Corticosteroids were commenced with clinical and biochemical improvement. This novel case highlights the need to consider sarcoidosis as part of the differential diagnosis for unusual multiorgan presentations and for early multidisciplinary involvement in such cases to permit optimal treatment. Sarcoidosis-associated kidney dysfunction in particular is usually attributable to granulomatous nephritis  or as a direct consequence of hypercalcemia .A 31-year-old man presented to the ED with epigastric pain and nausea, associated with generalized malaise and fatigue. The patient also described 2 days of mild, and 1 night of profuse, nonbloody diarrhea approximately 3 weeks before their attendance. He was a current smoker, working as a delivery driver, with no significant medical history and no regular prescribed medications. Over-the-counter medications included a multivitamin supplement and loperamide taken after the episode of profuse diarrhea. He had no history of illicit drug use. Initial investigations indicated acute kidney injury (Cr 241 μM) with hemoproteinuria, a raised amylase (191 U/L), and widespread pulmonary infiltrates visible on initial chest radiograph . The radTwo days after admission, the patient developed anemia (105 g/L) and thrombocytopenia  alongside an inflammatory response (c-reactive protein > 100 mg/L). A bone profile test revealed hypercalcemia . In this context, a blood film was performed, which showed red cell fragmentation (more than four per high-powered field), consistent with a microangiopathic hemolytic anemia . The patGiven the diagnostic uncertainty and multiorgan involvement, cross-sectional imaging was undertaken, showing marked perilymphatic ground-glass changes and nodularity in the midzones of both lungs, mediastinal lymphadenopathy, and splenomegaly . InvestiTransfusion of packed RBCs and platelets allowed a percutaneous kidney biopsy to be performed, which showed severe acute thrombotic microangiopathy (TMA), with no evidence of granulomata or interstitial nephritis A. Given Mycobacteria. Critically, the lymph node biopsies identified non-necrotizing granulomata consistent with sarcoidosis  and BAL of his middle lobe. The BAL, performed after the endobronchial ultrasound-guided biopsy, was blood-stained without prominent hemosiderin (indicating post-biopsy acute hemorrhage). The differential cell count was, as a result, difficult to interpret . BAL microscopy and culture was negative, including for coidosis B and, asEscherichia coli or Streptococcus pneumoniae, sarcoidosis has more frequently been linked to previous infection with Mycobacteria and Propionibacteria.,,To establish a final diagnosis for this case, we must consider whether the patient’s confirmed significant findings of granulomatous inflammation and TMA could be attributed to any other underlying condition. Both TMA and sarcoidosis can be associated with infection, but although hemolytic uremic syndrome is usually secondary to ,Given the widespread features of acute sarcoidosis and the sequence of events, a plausible explanation is that sarcoidosis represents the primary underlying pathology of this patient’s multiorgan dysfunction. We propose that sarcoidosis-driven hypercalcemia resulted in acute pancreatitis , which in turn led to TMA. Both sarcoidosis-induced hypercalcemia resulting in pancreatitis and this pathology leading to TMA are rare, but they have been described previously.Collaborative input from a multidisciplinary team including hematologists, nephrologists, respiratory physicians, histopathologists, and thoracic radiologists was critical to managing this case. We would therefore advocate early specialist input in such unusual cases of multiorgan pathology to permit optimal treatment to be provided and good clinical outcomes achieved.


This work proposes a novel design composed of graphene nanoribbons-based optofluidic tweezers to manipulate and sort bio-particles with radii below 2.5 nm. The suggested structure has been numerically investigated by the finite difference time domain (FDTD) method employing Maxwell's stress tensor analysis (MST). The finite element method (FEM) has been used to obtain the electrostatic response of the proposed structure. The tweezer main path is a primary channel in the center of the structure, where the microfluidic flow translates the nanoparticle toward this channel. Concerning the microfluid's drag force, the nanoparticles tend to move along the length of the main channel. The graphene nanoribbons are fixed near the main channel at different distances to exert optical forces on the moving nanoparticles in the perpendicular direction. In this regard, sub-channels embedding in the hBN layer on the Si substrate deviate bio-particles from the main path for particular nanoparticle sizes and indices. Intense hotspots with electric field enhancements up to 900 times larger than the incident light are realized inside and around the graphene ribbons. Adjusting the gap distance between the graphene nanoribbon and the main channel allows us to separate the individual particle with a specific size from others, thus guiding that in the desired sub-channel. Furthermore, we demonstrated that in a structure with a large gap between channels, particles experience weak field intensity, leading to a low optical force that is insufficient to detect, trap, and manipulate nanoparticles. By varying the chemical potential of graphene associated with the electric field intensity variations in the graphene ribbons, we realized tunability in sorting nanoparticles while structural parameters remained constant. In fact, by adjusting the graphene Fermi level via the applied gate voltage, nanoparticles with any desired radius will be quickly sorted. Moreover, we exhibited that the proposed structure could sort nanoparticles based on their refractive indices. Therefore, the given optofluidic tweezer can easily detect bio-particles, such as cancer cells and viruses of tiny size. Nevertheless, the vulnerability of cells under highly intense fields, low speed, and buffer incompatibilities impairs the efficiency of conventional microfluidic designs. Another technique to manipulate and sort cells in hydrodynamic flow control is based on either on-chip or off-chip, which is utilized to sort living cells due to less vulnerability of cells under a high electric field. However, this method suffers from the slow cycle time of the mechanical switch and the relatively large volume of fluids in each cycle5.The development of microfluidic and optofluidic systems is going to trigger a revolution in different fields such as physics, biology, chemistry, medicine, and photonics. The unique characteristics of such fluidic systems include fast and non-destructive performance, low cost, high efficiency, multiple applications, and compact footprint. Also, microfluidic cell sorting systems have received much attention with a variety of methods for active control of cell movements or flow, such as electrokinetic mobilization of fluids for bacterial cell sorting6. The radiation pressure of a focused laser beam resulting from the light momentum variations has been investigated to trap or push a single cell or particle in a fluidic medium without any physical contact. The imposed force on a particle depends on the size and optical properties of the particle as well as the surrounding fluidic medium. This optically-induced method opened a new promising approach to cell sorting networks in a microfluidic medium. The first single-cell sorting system was introduced at7, allowing the single cells to be trapped or sorted by imposed optical forces. Hence, this technique solved the problems mentioned regarding its non-invasive nature and ability to operate with a single cell.In this line of research, optical tweezers for cell trapping and manipulation were first introduced by Ashkin et al. in 19878 is based on optical far-field interactions. In these tweezers, the focal spot of a big numerical aperture (NA) objective has been used along prolonged paths to be more effective at far distances. However, these prolonged trap paths lead to drawbacks. First, observing the dynamic response of single molecules is impossible, and second, the diffraction limit restricts the sub-wavelength design of these tweezers. Therefore, an optical tweezer based on a near field or evanescent wave was developed to solve this limitation9. In the context of optical tweezers, it has been demonstrated that the optical force of an evanescent field is adequate to manipulate and trap microparticles at the interface of two media with different refractive indices, such as glass/water interfaces.The operation principle of conventional optical tweezers in the literature11.Nevertheless, such evanescent waves are not strong enough to trap and manipulate nanoparticles. Therefore, a metallic tip or nanoaperture has been employed for exciting surface plasmons waves (SP) to improve near-field enhancement. However, despite their ability to displace nanometer-sized single cells, the induced surface plasmons in a metallic tip introduce huge absorption losses reducing trapping stability16, modulator18 photodetectors23. Especially in the recent years graphene plasmonics applications in optical tweezers (PT)31, have been introduced to address mentioned drawbacks and have been utilized in optofluidic systems to sort nanoparticles. For instance, in25, active graphene plasmonic tweezers and size/RI-based nanoparticle trapping and sorting with radii in the range of 5–50 nm is proposed. The structure is illuminated by a laser beam in the mid-IR frequency range of 4–8 µm and its wavelength and intensity are kept constant even for sorting functionality. Each unit cell of the structure is composed of a graphene layer on top of a metallic nanoring which is embedded in SiO2. Strong hotspots with field enhancements reaching values as high as 150 are obtained inside the rings with no need for sharp edges conventional in plasmonic structures. Graphene, as a two-dimensional material, with superior optoelectronic characteristics such as broad-band light absorption, high electrical and thermal conductivity, ultrafast charge carrier dynamics, and gate tunable charge carrier density is a promising alternative to metallic counterparts for designing plasmonic structures. However, the unique features of graphene are vulnerable to its substrate, originating from the interaction of each graphene atom with the surrounding medium32.In recent decades, graphene plasmonic-based applications have been attracted significant attention such as sensors33, Ni34, Ru35, Pt36, SiC38, and SiO2 for graphene have been studied so far. Reports demonstrate that SiO2 as a conventional and widely used graphene substrate deals with problems such as carrier mobility reduction via scattering in the charged surface states, impurities, substrate surface roughness, and surface optical phonons. Therefore, a substrate is required for graphene-based structures without limiting its unique properties. Meanwhile, studies show that  hBN with promising features as the graphene substrate40 can surpass other materials.To improve graphene performance, different substrates, such as Co40. This improvement originated from graphene mobility due to the higher reduction of surface impurities associated with the low lattice mismatch between the graphene and its hBN substrate. The graphene/hBN lattice mismatch is only 1.7% which is ten times smaller than graphene's conventional substrates like SiO240. The flat surface of hBN, no dangling bonds, and no trap charges on the hBN surface make it a perfect substrate for a 2D graphene sheet41. High carrier mobility improves the plasmonic wave propagation and the optical response of graphene42. In addition, hBN has excellent physical properties such as high-temperature stability, corrosion resistance, sizeable optical absorption43, neutron capture interface, ultra-long carrier lifetime39, and significant negative electron affinity44. The unique feature of hBN/ graphene sandwich is investigated thoroughly in the graphene plasmonics Fabry–Perot wave interferometer photodetector19 in which by using hBN as an substrate for graphene in compare with the conventional substrates such as SiO245. In this work we represented that using hBN instead of SiO2 reaches the responsivity of photodetector more than 10 times larger, more over due to high graphene mobility on hBN, the photodetector bandwidth experienced an immense improvement as well as photodetection speed. However, using hBN due to 2D nature of this material causes some irregularities on graphene features which is completely studied at our previous work46.Dean et al. demonstrated the first graphene-based transistors using the hBN substrate with significant improvementsx), thus directing toward the adjacent nanoribbons where the electric field is significantly confined. The electric field’s hot spots on the graphene nanoribbons are 900 times larger than the incident one. The electric field enhancement on the graphene nanoribbons is significantly sensitive to graphene chemical potential. Therefore, the optical forces in the vertical (x) direction on nanoparticles can be tuned by correctly choosing the gate bias and the optimized gap distance between the main channel and graphene nanoribbons. Thus, a desired deviation of the nanoparticle allows us to direct it toward the outlet branches. The resonance wavelength of graphene ribbons is adjusted by tuning the graphene Fermi level, allowing us to determine the operating wavelength interval of the proposed optofluidic system. Finally, repetition of this process leads to individual particles with desired sizes or refractive indices being sorted and directed to outlet branches.This study proposes a novel structure composed of graphene nanoribbon embedded in hBN to trap nanoparticles with radii in the 2.5–50 nm range and sort below R = 2.5 nm nanoparticles. The principal mechanism of nanoparticle manipulation relies on exciting graphene plasmon with a parallel-polarized incident light concerning the graphene surface. An extra optical force is exerted on nanoparticles via graphene nanoribbons perpendicular to the liquid drag force. The moving nanoparticles inside the liquid deviate from their original path in the main channel in response to exerted optical force in the vertical direction (Fn = 1.57 for radii in the range of 2.5 nm to 50 nm. The fluidic medium is considered to be water with n = 1.33. The electromagnetic wave simulation using the Maxwell Stress Tensor (MST) method is performed to calculate the imposed optical forces numerically. The primary channel is where the nanoparticles with a liquid are pushed in, as seen in Fig. Figure 1), all the particles are placed in the middle of the ribbon as indicated by the dashed line in Fig. 1 in the x direction (Fx). Nanoparticles continue to move under the influence of liquid force in the y-direction without deviation in the x-direction. However, when the particle moves in the y-direction and reaches closer to the sub-channel graphene ribbon (GR2), the particles experience a gradient force in the x-direction exerted by the GR2, leading to deviation of a specific (larger) nanoparticle in the x-direction. Large particles sense stronger forces in the x direction, so the deviation of a large particle is more significant than the smaller ones. Therefore, the larger particle changes its path toward the GR2 and is filtered out from the main channel. Due to interaction with the GR2 (which is shown later) the Fx component of force felt by the nanoparticle became zero but it still has Fy to push the nanoparticles toward outlet.1.From Fig. 3) is placed in the main channel to push back undesired deviation to the center of the main channel.It is worth mentioning, despite that sorting the larger particle in step.1 the smaller nanoparticles also felt force in the x direction and experienced a small deviation from the center of the main channel. Therefore, another graphene nanoribbon  method and Perfectly Matched Layers (PMLs) are employed in all direction in our simulations. The simulation domain's height  is 5 µm, and the plane wave source is placed 2 µm above the graphene surface.In the optical analysis, we consider a total field-scattered field (TFSF) plane wave source with a constant intensity of 0.6 mW/ µm47, its surface conductivity is described by Random Phase Approximation (RPA) which is given by: ħ is the reduced Plank constant, T is the temperature, ω is the angular frequency, μc is the chemical potential, Γ is the phenomenological scattering rate that is assumed to be independent of energy εσ, and fd (εσ) is the Fermi–Dirac distribution function. Real and imaginary parts of the Surface conductivity of graphene versus chemical potential are illustrated in Fig. Graphene is modeled as a two-dimensional sheet in FDTD analysis, and according toentclass1pt{minimang = Cg (Vg-Vdirac)/q, in which Cg is the gate capacitance, Vdirac is the applied gate voltage corresponding to Ef = 0 in graphene, Vg is the applied voltage to the gate and q is the unit charge. Accumulating charge carriers in the graphene shift the Fermi level so that this shift versus the gate voltage can be calculated via Eq.  are extracted from42. Also, the permittivity of the Si is taken from51 and illustrated in Fig. In the given nanoparticle sorter, the hBN is modeled as anisotropic bulk material with parallel and perpendicular real and imaginary parts of permittivity functions obtained from Eq. . This ma52. To fabricate graphene nanoribbon on an hBN surface a mechanical transfer method52 to deposit graphene on hBN substrates can be used which is a special method to transfer graphene from one substrate to an exact location on another substrate (in this case an hBN flake). this method can be used to fabricate multilayer graphene nanoribbons53. In this method, extreme care is taken to reduce water residues and this is named the “dry transfer method”. They adopted the dry transfer method to our needs. A dry transfer method consists mainly of four steps as illustrated In step A the PMMA (carrying the graphene) is suspended in a plastic window that has been attached to the chip by using double-sided tape to the PMMA side. Next in step B, sacrificial PVA film is dissolved in DI water to release the PMMA film from its substrate. The graphene is on top of the PMMA so it will never be in contact with water. In step C they adhered the PMMA membrane to an aluminum transfer slide, which is clamped to a mask aligner modified. During the transfer process, they fix the hBN-containing substrate on the holder. In step D, using the optical mask micro-manipulators, they align the graphene flake to the hBN crystal and lower the polymer side onto the substrate. When the polymer touches the substrate, it makes strong contact with the SiO2 substrate. Then, they turn off the nitrogen valve of the mask aligner and down the holder substrate along with the PMMA polymer attached to it. They finally put the substrate with target hBN flake on a custom-made heater that they set to 110˚C to enhance adhesion between graphene and hBN for at least 10 min. Next, the sample is allowed to cool down and the PMMA is removed with acetone and isopropanol (IPA). As chemical cleaning with organic solvents always leaves some residues, they anneal the samples as well. At this stage, they heat the samples slowly to 400˚C in a tube oven in forming a gas environment and anneal them there for ∼3 h before slowly cooling them down to room temperature. This treatment is very effective in removing polymer residues from the transfer.The graphene-hBN stack can be created by dry-transferring graphene over thick mechanically cleaved hBN crystal, as described in2.Since this fabrication method requires only one cleaning step, it allows for fast device preparation of graphene on hBN with little bubbles and wrinkles. Electrical transport measurements of the graphene devices on hBN have mobilities and carrier inhomogeneity that are almost an order of magnitude better than devices on SiO54. The exerted average optical force is given by:S enclosing the particle, and TM is the Maxwell stress tensor obtained by Eq.  the scattering force is negligible. In order to evaluate optical forces acting on a particle at first, we integrate MST on the surface of the particle55, which is described by:µf, v, a, and h are the viscosity of water taken to be 0.89 mPa.s at the room56, the particle velocity, particle radius, and the distance between the surface and the center of the particle, respectively.When the particle is guided by the evanescent field and moves along a planar substrate in a flow channel and is pushed by a scattering force depending on its radius and distance from the substrate, it experiences the Stokes dragAs discussed earlier, an increment of the graphene Fermi level makes the plasmonic effect more robust and enhances the electric field at the surface of the ribbon. Figure According to Fig. x exerted on nanoparticles of different sizes, which are fixed at the center of the main channel, where the graphene ribbon in the second channel has a 117 nm gap from the main channel. Larger particles experience a more significant force. In Fig. x is calculated for the constant source wavelength of 4.44 µm, which is the plasmonic resonance wavelength of graphene ribbons. For nanoparticles with different sizes, the value of µc is constant. Figure Here, we suppose a structure with only two channels for analyzing the sorter's function. One of these channels is the main and, and the other is located at the substrate with a definite gap and their width are 120 nm in x-direction. Figure Figure x and Fz have maximum values at the center of the ribbon. In addition, Fy is almost negligible in the y-direction. It is worth mentioning that here the dynamic analysis is not investigated yet, and the figures show that particles of any size can be trapped by nanoribbons. The dynamic state of the proposed system will be vastly investigated in the next section.Figure x for five various nanoparticles when they are fixed at x = y = 0. This figure shows that the force decreases by increasing the distance between the nanoparticle and ribbon from 10 to 170 nm. Furthermore, the width and length of the graphene nanoribbon can impose an electric field enhancement such that the exerted force of the nanoparticle is affected, which is shown in Fig. x exerted on the nanoparticle has the maximum value in the x-direction. In addition, particle size and optical forces can vary the drag force felt by nanoparticles induced by microfluidic flow in the inlet. Figure The gap between nanoparticles and graphene ribbon significantly affects the optical force experienced by nanoparticles moving in the main channel. The exerted force increases by decreasing the gap between them. Figure x on a nanoparticle, it experiences a different trajectory. However, when the gap is fixed to its optimized value, the nanoparticle is trapped above the ribbon. In contrast, nanoparticle keeps moving at the main channel at large gaps.We have statically investigated the parameters that affect the manipulation of nanoparticles. In the following, dynamic structure simulations are evaluated, giving us more exciting information about the designed structure. Here we investigate the particle's movement along the channel regarding time for differing gaps and sizes. Since the gap variations affect the induced Fx increases, and the particle deviates from the main channel and moves toward the ribbon. At the small gap, Fx reaches a high value.Figure x has damped the x-direction movement of the particle, and it became constant. In other words, the ribbon electromagnetic field traps it. After the particle is trapped, it moves along the y-direction concerning the drag force shown in Fig. x has the maximum positive value, which means the particle felt force in the + x direction. However, due to the large gap and low exerted force on the particle, the particle's position has no considerable change in the x-direction and keeps moving in the main channel.The particle passes through the ribbon due to the particle's momentum, similar to Fig. x in comparison to the trapped particle, it remains at the main channel, as shown in Fig. Notably, when the larger particle is sorted, the smaller particle deviates from its main path. However, due to minor Fx takes more time to reaches steady-state, in another word particle 2 or 3 times path the ribbon until it trapped at the center of the ribbon according to Fig. z reaches its maximum value therefore Fz peaks each time the particle paths the center of the nanoribbon. Figure Figure One of the notable features of this structure is sorting tiny particles. As shown in Fig. BT for both particles. On the other hand, the potential chemical peaks at around 120 and 90 nm, equal to the G of both particles, which means the trapping potential has the maximum value at the left side of the ribbon. Likewise, the force change sign at potential chemical peaks means that when the particle path on the left side of the ribbon Fx tries to pull back to the ribbon, it takes more negative force to overcome its initial momentum due to the particle velocity. It is clear from both figures that the negative sign of force is larger than the positive sign, resulting from the initial momentum of the particles.Figure Figure th to 140 nm, the smaller particle which has a radius of R = 15 nm owns an undesired deviation of Δx = 25 nm, and as can be seen, it reaches to the edge of the main channel, which is not desirable. Figure As shown in Fig. X, it returns to the left of the ribbon, and the nanoparticle experiences a negative velocity. Eventually, the speed direction reverses, and particles fall into the trap in a sinusoidal pattern by repeating these steps; the particle with R = 15 nm and G = 125 nm is damped, and its velocity reaches zero as expected at the center of the ribbon. In contrast, the inset of Fig. We analyzed the impact of nanoparticles' refractive index (RI) variation in manipulation. by decreasing the nanoparticle's RI, the differential between medium RI and nanoparticle decreases, which leads to a weak electromagnetic field and so that the exerted force on the nanoparticle decrease. as Fig. Finally, the threshold gaps between various particle sizes are explored. Figure c, about 1.15 eV. Nevertheless, the optical force dropped sharply by increasing or decreasing µc from 1.15 eV. It means that a minor change in graphene chemical potential results in changes in optical force felt by nanoparticles. Therefore, the proper and suitable graphene chemical potential can be obtained by adjusting the biased gate voltage. Figure As we claimed at first, the proposed structure can also sort nanoparticles only with one subchannel or nanoribbon at a constant gap. The physical mechanism is the same as the threshold gap examined previously; however, instead of changing the gap to control exerted force on the nanoparticles, the shift in graphene chemical potential by applying a gate voltage to the Si substrate has been used to control exerted force for each nanoparticle. To clarify the algorithm for sorting particles with fermi energy, Fig. By analyzing the threshold gaps and the graphs obtained from them, an equation can be proposed for both methods stated in this article, in which only with an error of less than 2.5 nm, the threshold gap and the potential energy of the graphene threshold for sorting all obtained nanoparticles with the desired radius. But not only for particles with a certain radius such as 30, 20, 15, etc. Rather, for any desired radius, one can easily find the threshold gap as well as the threshold form for sorting that specific radius. Equations th represents the threshold gap shown in Fig. –3 and c = −1695.In Eq. c represents the threshold graphene nanoribbons’ chemical potential for sorting and deviating any specific nanoparticles with radii of R. the value of a1, b1, and c1 are constant and are equal to a1 = 43 × 10–3 b1 = 8 × 10–3 and c1 = 1.574.Moreover, to the gap threshold as shown in Fig. This article presents a structure for manipulating and sorting nanoparticles using the optical and electrical advantages of graphene nanoribbons embedded in the hBN substrate. In this structure, two methods are used to separate the particles, one is through the distance of the ribbon with the main channel in x direction , and the other is through the chemical potential of graphene. It was also shown that the presented structure could sort particles with a radius below 2.5 nm, making it one of the few structures that can trap and sort nanoparticle particles below 5 nm in diameter. In addition, both methods showed that the presented structure could sort the particles entering the liquid according to their refractive index. The primary physical mechanism of both methods in the proposed structure is to control the force on the particle moving inside the channel, which can be done through the gap between the ribbon and the channel or the potential chemical level of the graphene. The presented structure can be one of the most used structures and open a door for the future of nano-biosensors. Also, this structure makes it possible to sort and manipulate all kinds of viruses or any desired particles in the liquid with very high accuracy of 1 nm. Another advantage of the proposed design is its facility to fabricate, and there is no difficulty in the fabrication process of the proposed structure, or second-order effects and irregularities arise from errors in the fabrication process of the structure. furthermore, by using several animations in the main text and as supplemental information the performance and physical mechanisms of the understanding of the proposed structure became very clear. .Supplementary Information 1.Supplementary Information 2.Supplementary Information 3.Supplementary Video 1.Supplementary Information 4.Supplementary Information 5.Supplementary Information 6.Supplementary Information 7.Supplementary Information 8.Supplementary Information 9.Supplementary Video 2.