We explore the substrate-dependent charge carrier dynamics of large area graphene films using contact-free non-invasive terahertz spectroscopy. The graphene samples are deposited on seven distinct substrates relevant to semiconductor technologies and flexible/photodetection devices. Using a Drude model for Dirac fermions in graphene and a fitting method based on statistical signal analysis, we extract transport properties such as the charge carrier density and carrier mobility. We find that graphene films supported by substrates with minimal charged impurities exhibit an enhanced carrier mobility, while substrates with a high surface roughness generally lead to a lower transport performance. The smallest amount of doping is observed for graphene placed on the polymer Zeonor, which also has the highest carrier mobility. This work provides valuable guidance in choosing an optimal substrate for graphene to enable applications where high mobility is required. For example, graphene has already been implemented into a broadband image sensor array for enhanced photodetection4 as well as memristors based on layered two-dimensional materials5. Graphene was also demonstrated to be a sensitive chemical and biological sensor8. With the development of large-scale production techniques such as epitaxial growth or chemical vapor deposition (CVD), large area graphene shows increasing promise for implementation into macroscale modern devices9.Graphene, an atomic layer of carbon atoms arranged in a honeycomb lattice, is not only a rich playground for uncovering new physical phenomena, but also a potential component in future electronic and optoelectronic technologies10. Intrinsic limiting factors include scattering from lattice defects, grain boundaries14, or phonons16. Due to the formation of grain boundaries and defects during the CVD growth, such scattering mechanisms could be more pronounced in large-area graphene compared to micron-scale mechanically exfoliated samples18. Among extrinsic limiting factors, scattering due to charged impurities is known to play a significant role19. Charged impurities can be present in the underlying substrate20, trapped between the film and substrate21, or on the surface of graphene in fabrication residues22.Among its many properties, the high mobility of the massless Dirac fermions in graphene plays a key role in the implementation of high-speed electronic devices. Therefore, it is imperative to develop better understanding and control over the factors that affect scattering mechanisms in graphene films. Factors that limit large-area graphene’s mobility can be either intrinsic or extrinsic2, Si3N4, quartz or silicon is reported to have carrier mobilities varying between 500 and 10,000 cm2V−1 s−125. Efforts to engineer substrates that minimize the presence of trapped charges and mechanical deformations led to three orders of magnitude improvement, with the highest mobilities (larger than 106 cm2/(Vs)) reported in freely suspended devices27 or on top of atomically flat boron nitride (BN) crystals28. It is therefore critical that the graphene-substrate interaction be well understood for successful integration of large-area graphene films with high mobility. Substrates that ensure high mobility for graphene films could be exploited for improving device performance in future graphene integrated electronics.Graphene supported by common substrates such as SiO230. Electrical transport was also used to investigate large-scale graphene deposited on several dielectrics commonly used in the semiconductor industry. The highest mobility was achieved when graphene was placed on Si3N4, which outperformed SiO2, HfO2, Al2O3, and tetraethyl orthosilicate. This work indicated that carrier density fluctuation caused by the substrates is one of the main contributing factors for mobility degradation31. Other studies relied on time-resolved THz spectroscopy to explore the substrate effect on graphene placed on sapphire, silicon, germanium, polyethylene naphthalate (PEN), polyethylene terephthalate (PET), and quartz33. This technique provided information about the graphene DC conductivity, but the experimental spectral bandwidth, limited to frequencies up to 3 THz, could not resolve features attributed to carrier scattering. As a result, no information was obtained on carrier density or mobility. Finally, there has been more work that measured36 and even spatially resolved37 the transport properties of wafer scale graphene using THz spectroscopy. These studies, however, are restricted to only one specific substrate, or do not investigate the substrate dependent dynamics at play.To date, graphene-substrate interactions have been studied in devices by measuring the unpumped/non-excited carrier dynamics with both optical techniques and electrical transport techniques. For example, far-infrared spectroscopy (3–16 THz) was used to characterize graphene on different polar dielectric and organic polymer films. Graphene on hexamethyldisilazane (HMDS) notably exhibits a mobility four times higher than on SiO38. Moreover, the THz technique is sensitive to the Drude mobility instead of the field effect mobility. For electrical measurements, the measured field effect mobility and conductivity is affected by surface defects such as grain boundaries, wrinkles and bubbles. Time-domain THz spectroscopy is sensitive to the microscopic conductivity averaged over the distance travelled by an electron during one oscillating cycle of the optical field25. Since this length typically corresponds to few tens of nanometers in graphene11, while defects occur on the micrometer, or even millimeter scale, the Drude mobility and conductivity obtained with THz spectroscopy is minimally sensitive to large scale surface imperfections. Previous works compared the THz technique with other characterization methods relying on van der Pauw structures25, back gate measurements32, a micro four-point probe39, or micro Raman spectroscopy39. These studies confirmed the potential of THz spectroscopy to remotely map the electrical properties of large graphene sheets and optimize the integration of graphene into electronics or opto-electronics devices37.Here, we perform time-domain terahertz transmission spectroscopy over a bandwidth contained within 0.5 to 5.5 THz to measure graphene’s transport properties when supported by substrates with different charged impurity densities, dielectric constants, and surface roughness. Our THz spectral window, extending beyond the limit of most commercial systems, is sufficiently broad to capture the spectral-dependent change in conductivity associated to the Drude roll-off frequency and therefore allows for measurement of both carrier density and Drude mobility. In comparison to other characterization methods based on electrical measurements, THz spectroscopy is a non-invasive technique that does not alter the graphene structure or rely on the deposition of electrical contacts, which composition and configuration often affect the measured transport parameters1. We compare the mobility of graphene deposited on different materials: two gate dielectrics (SiO2 and Si3N4) which are traditional materials for computational-based applications, silicon with three doping concentrations, and a hydrophobic, flexible, transparent polymer (Zeonor). We find that substrates with minimal amount of charged impurities and substrates that are flat generally exhibit the highest carrier mobilities. Notably, graphene on high-purity silicon and insulating Zeonor outperform the popular gate dielectrics. Our results guide the field of graphene integrated technologies, by providing valuable insights into the transport potential of graphene supported by substrates commonly used in devices.The selection of substrates in this work is guided by the promise for graphene to be implemented into “beyond Moore” technologies2 in Fig. 2D/IG = 1.94) shown in Fig. In this work all samples are identically prepared, using graphene synthesized by CVD on Cu foil and transferred onto a substrate as schematically represented in Fig. 11, such that:41. The frequency-dependent Drude model, which has been broadly used to describe carrier intra-band scattering behavior in graphene36, yields:σDC is the DC conductivity, ω is the radial frequency, and τ is the scattering time. As a result, we are able to extract values for both σDC and τ from the THz data. In general, the analysis of time-domain THz measurements is restricted to data points within a carefully selected spectral window centered around the maximum THz signal, where experimental noise is considered negligible. Here, we use instead a scan-to-scan statistics to include a larger bandwidth while error bars objectively determine the precision of each spectral data point. More specifically, experimental data are fitted to the Drude model , Si with three doping concentrations corresponding to a resistivity of 10 kΩ cm (intrinsic doping), 15 Ω cm (p-doped), and 5 Ω cm (p-doped), and finally the flexible polymer Zeonor, a cyclo-olefin copolymer. We note that all bare substrates display high transparency to our broadband THz probe. Assuming a diffusive Drude-type transport regime45, we can then calculate graphene’s carrier concentration (NS) and the mobility (μ) from the extracted σDC and τ using the following relations:vF≈ 106 m/s. As a result, THz measurements enable an effective and non-invasive method for probing the influence of the substrate on the transport properties of graphene films.We use the experimental procedure described above to obtain the parameters σDC, τ, NS and NS in graphene is strongly dependent on the substrate. This variation, by more than an order of magnitude, can be attributed to the densities of free and trapped charges in the substrate, which have previously been identified as two dominant parameters affecting NS43. For the insulating substrates, trapped charges are particularly relevant, as those present at the surface may directly transfer charges to graphene and those beneath the surface may still capacitively induce charges in graphene. For the conductive substrates, NS is largely due to direct charge transfer. In our experiment, the largest values of NS are obtained for graphene placed on doped Si and approach 1013 cm−2, corresponding to graphene’s Fermi level being 350 meV away from the Dirac point. This value is comparable to epitaxial graphene grown on SiC46. Insulating substrates, including typical gate dielectrics (SiO2 and Si3N4), high-resistivity Si (ρ = 104 Ω cm) and the polymer Zeonor (ρ = 1016 Ω cm), lead to a lower NS. The lowest doping level we measured corresponds to graphene on Zeonor (NS = 8 × 1011 cm−2), indicating that this substrate has a minimal amount of free and trapped charges contributing to the doping of the 2D material on its surface.In Fig. NS. We obtain higher mobilities for less doped samples, consistent with the notion that substrate charged impurities create an electrostatic potential that limits the mobility20. Interestingly, graphene on high-resistivity Si shows a higher mobility than the one on gate dielectric substrates although these samples have a similar carrier concentration NS. This result can be attributed to a more uniform electrostatic potential profile at the surface of the high-resistivity Si substrate, which results in a longer scattering time τ and, according to Eq.  and the highest mobility, even though this substrate has the lowest dielectric constant among the samples measured. This indicates that the screening of charged impurities in the substrate is not necessarily the main contributor to the high mobility, but other factors come into play, such as the density of trapped and free charges in the substrate, as discussed previously. In general, Fig. The dielectric constant κ of the substrate or environment can play an important role in the transport properties of graphene; larger values of κ imply the ability of an environment to readily screen charged potentials created by trapped scattering centers, and therefore enhance the scattering time and, consequently, the carrier mobilityRq) of the seven substrates used in this experiment  and vice-versa. For example, we measure τ = 91 fs for Si-10 kΩ cm (Rq = 220 pm) while τ = 36 fs for wet SiO2 (Rq = 380 pm). However, we note two exceptions in our experiment: (1) graphene on doped Si features a short scattering time although the substrate is relatively smooth. This suggests that Coulomb scattering could be a dominant mechanism in this case. (2) At the other extreme, graphene on Zeonor has a relatively long scattering time while the substrate roughness is higher, Rq = 650 pm. To assess the adhesion of graphene to Zeonor, we measured the roughness of the graphene sheet on Zeonor, which shows a smoother morphology (Rq = 520 pm), suggesting relatively poor adhesion of the graphene to the substrate. As a result, graphene may experience a reduced influence from the substrate roughness. Note that the mobility in Fig. 51 and HMDS30 demonstrated reduced ambient doping and hysteresis compared to those on SiO2.Although much less systematically studied, substrate roughness can also affect the carrier mobility in graphene since a smooth interface contributes to reduced strain of the film or eliminates wrinkles and edges that could induce scattering. Using atomic force microscopy, we measure the roughness , for graphene supported by distinct substrates. When comparing the results on different substrates, we find the highest mobility for graphene placed on pure silicon and the polymer Zeonor, which outperformed commonly used gate dielectrics. This highlights that the densities of trapped and free charged impurities in the substrate are likely key limiting factors of the graphene film’s mobility. We also find the mobility of devices to be generally improved for substrates that are smoother, except for graphene on Zeonor. In this case, we interpret the high mobility to be due to both the poor adhesion between Zeonor and graphene, minimizing the substrate effect, and to the low density of trapped charged impurities at the interface. A flexible polymer, therefore, can be considered as a promising alternative to some gate dielectrics. These results provide valuable guidance for the effective integration of graphene into technological platforms where high mobility is necessary.In summary, we have demonstrated the implementation of terahertz transmission spectroscopy for probing the equilibrium transport properties of CVD graphene supported by seven substrates, distinct in their density of charged impurities, dielectric constant and surface roughness. We find that the resulting conductivity spectra for graphene films agree well to a Drude model for intraband behavior, consistent with other reports. We have demonstrated a method for weighted Drude fitting based on statistical averaging and extracted transport properties , which is transferred onto a substrate using a standard PMMA-based wet etching technique54. These pulses are focused onto a nonlinear GaP crystal where THz transients are generated by difference frequency mixing. The time-domain detection relies on electro-optic sampling inside a second GaP crystal55. The measurements are performed in a transmission geometry. Apodization of the time-domain signal allows us to exclude Fabry-Pérot echoes. Therefore, only the pulse directly transmitted through the sample is considered in extracting the graphene transport parameters. The samples, at room temperature and under normal ambient conditions, are placed at the focus of an off-axis parabolic mirror, with a numerical aperture NA = 0.5, focusing the THz beam to a 400 µm diameter (1/e2) at 1 THz. The optical probe size is significantly larger than any local defects, such as wrinkles, bubbles and other imperfections revealed by AFM images of the samples. Large scale anisotropy reported in previous work37, is accounted for by performing measurements at different locations on the sample at a ~ 5 mm separation. Note that we purge the system with dry air (< 0.5% RH) to minimize THz absorption in water vapor.The time-resolved THz system is based on a near-infrared source delivering 180 fs pulses at 1035 nm, which can be compressed to ~ 50 fs pulses using spectral broadening in a gas-filled hollow-core photonic crystal fiber and dispersion compensation opticsSupplementary Information


Lithium-ion capacitors (LICs) are attracting increasing attention because of their potential to bridge the electrochemical performance gap between batteries and supercapacitors. However, the commercial application of current LICs is still impeded by their inferior energy density, which is mainly due to the low capacity of the cathode. Therefore, tremendous efforts have been made in developing novel cathode materials with high capacity and excellent rate capability. Graphene-based nanomaterials have been recognized as one of the most promising cathodes for LICs due to their unique properties, and exciting progress has been achieved. Herein, in this review, the recent advances of graphene-based cathode materials for LICs are systematically summarized. Especially, the synthesis method, structure characterization and electrochemical performance of various graphene-based cathodes are comprehensively discussed and compared. Furthermore, their merits and limitations are also emphasized. Finally, a summary and outlook are presented to highlight some challenges of graphene-based cathode materials in the future applications of LICs. With the increasing global energy consumption, the growing concerns of the depletion of fossil fuels, the corresponding climate change and environmental pollution have arisen ,2,3. Thu+ diffusion rate in the bulk electrode and low electrical conductivity of the cathode lead to inferior power density, while the continuous and usually uncontrollable decomposition of electrolytes and the serious deterioration of material structure result in a poor cycle life for LIBs . . 2CO3 anmAh g−1) . Specififor LICs ,103. Forout 5 nm f. Conseqout 5 nm g–h.2) nanoparticles were uniformly deposited onto the graphene oxide sheets via an aqueous-solution-based regular deposition process. Then, the SnO2/GO suspension was spray-dried to obtain a spherical composite, which was heated to induce the selective decomposition of the graphene adjacent to the SnO2 nanoparticles. It is noteworthy that the temperature should be carefully adjusted to be lower than the carbon combustion temperature in the catalytic carbon gasification process. Finally, the spherical SnO2/rGO was refluxed in HI to etch the catalysts and to reduce GO. The as-prepared HG has a spherical morphology and porous structure with rich in-plane holes of about 5 nm corresponding to the metal oxide size  with abundant in-plane pores using this method . The synide size b. The N2esopores c. This resopores c, which esopores d. As exp kh kg−1 e. The ouIn summary, benefitting from the 3D continuous porous structure and inherently high conductivity of graphene, pure graphene-based porous materials could deliver high capacity and superb rate capability and thus achieve high energy and power densities and cycling stability when used as a cathode in LICs, as summarized in Benefitting from the layered structure, graphenes are good 2D building blocks for constructing 3D porous composites . Elabora2 g−1 and excellent bulk conductivity (up to 303 S m−1) because of the introduction of graphene. Taking the sucrose-based 3DGraphene, for example, it achieves an ultrahigh SSA of 3355 m2 g−1 with a well-controlled pore size of primarily 2–6 nm for the samples of optimized ratio  with GO sheets and biomass or polymers  using standard industry steps of in situ hydrothermal polymerization/carbonization and KOH activation a 24]. T. T24]. Ted ratio e,f, makiapacitor g 74]. L. L2 g−1 2 g−1 and the largest pore volume of 1.67 cm3 g−1 were obtained  and a capacitance retention of 84.8% after 5000 cycles. Sun et al. fabricated a single carbon nanotube (SWCNT) and graphene composite (SG) by inserting the SWCNT into the space between the graphene nanosheets [In the previous reports, conductive extra spacers  were usually introduced to prevent the restack of graphene-based materials by forming 3D composites, which leads to high SSA and/or electrical conductivity, and thus excellent specific capacitance and rate capability could be obtained ,121. Simnosheets . As show2 anode, the full LIC cell exhibited an ultralong cycling life with 96% capacity retention after 10,000 cycles at 5 A g−1  can also be applied as spacers to inhibit the restacking of graphene sheets considering their unique merits of high conductivity, excellent flexibility and high capacity derived from fast redox reaction. Ock et al. proposed a high-capacity and high-rate PANI@rGO and used it as a capacitor-type electrode . PANI@rG 5 A g−1 d. Moreov kW kg−1 e. The en3 treatment, the final product was obtained. N-GMCS possesses a hierarchical porous structure, 3D conductive network as well as high packing density (0.6 g cm−3), making it a promising capacitor-type electrode for high-energy devices. As expected, LICs with N-GMCS as the cathode delivered maximum energy and power densities of 80 Wh kg−1 and 352 kW kg−1, respectively (corresponding to 66.7 Wh L−1 and 292 kW L−1) , which always leads to inferior volumetric energy density . Therefo kW L−1) b.2 g−1 and its electrode density is still as high as 0.71 g cm−3, which is around 173% of that of AC. Hence, although AC/G-57 shows relatively lower gravimetric specific capacity compared with pristine AC, it has the largest volumetric specific capacity of 45 mAh cm−3, which is 137% of AC and 147% of HPGM, respectively  composite as the capacitor-type cathode for high gravimetric/volumetric energy density LICs . The typectively g. Furtheectively h. Conseqectively i,j. A siBased on the above discussion, graphene-based 3D composites show obvious advantages compared with reduced GO and pristine porous graphene, as summarized in LICs possess the merits of a high energy density, high power density, large operation voltage, wide working temperature range and long cycling stability, and thus are considered to be one of the ideal energy storage devices to overcome the disadvantages of batteries and supercapacitors. Although LICs have the potential to bridge the gap between batteries and supercapacitors, their electrochemical performance still fails to reach the requirements of commercial applications. Especially, the unsatisfactory energy density of state-of-the-art LICs is one of the main obstacles preventing their applications, which is mainly due to the low capacity of the capacitor-type electrode and the kinetics and capacity imbalances between the cathode and anode. For instance, traditional capacitor-type materials such as AC suffer from inferior specific capacity and poor rate performance because of a relatively low SSA and electrical conductivity. Hence, developing high-capacity capacitor-type materials is significantly important to obtain high-energy LICs. Thanks to their unique 2D structure, high electrical conductivity, large SSA, tunable surface chemistry and excellent chemical and electrochemical stability, graphene-based cathode materials have demonstrated remarkable achievements in LICs. In this review, a systematic summary of graphene-based capacitor-type materials has been presented. It could be easy to conclude from the above results that graphenes, either as active materials or as building blocks to form composites with other materials, have shown great potential in capacitor-type cathode candidates for LICs.(1)High-capacity capacitor-type materials are urgently needed. To match the high capacity of battery-type anodes, developing cathode materials with improved capacity is the top priority. The cathode stores energy through a physical adsorption/desorption process at the electrolyte/electrode interface, which leads to a fast charge/discharge rate. On the other hand, the non-Faradaic energy storage mechanism also results in low capacity because it is critically influenced by the SSA. A high SSA could provide more active sites for ion adsorption and, to a certain extent, the capacity is raised with the increase in the SSA. However, it should be pointed out that not all the surface can be accessible by the electrolyte ions . Therefo(2)The preparation of graphene-based cathode materials at low cost is one of the critical factors for large-scale applications. Although pure graphene-based porous materials can serve as outstanding capacitor-type electrodes due to their high electrical conductivity and large SSA, the high cost impedes their further commercial utilization. Forming composites with other materials is a facile but feasible method to solve this problem, such as biomass or polymer/graphene hydrogel-derived graphene-based 3D porous materials initially proposed by Chen’s group . In such(3)Developing battery-type materials with a high rate and long-term stability is another big challenge but imperative issue. High-capacity anodes ensure the high energy of the full cell. However, the high energy density of state-of-the-art LICs could only be realized at the cost of low power output because of the sluggish redox reaction and/or inferior electrical conductivity of battery-type anodes. Hence, designing nanostructured materials with tunable porosity and compositing with highly conductive materials are always applied to achieve high-rate anodes. These strategies could help to reduce the capacity and kinetics imbalances between the cathode and anode, leading to improved energy and power densities . With th(4)The volumetric performance of graphene-based materials should receive more attention for commercial applications. Graphene-based cathode materials have shown enhanced gravimetric capacity compared with commercial AC. However, their large SSA and highly porous structure result in a low taping density and consequently low volumetric energy density, which is a big obstacle for practical utilization. In addition, more binders and solvents are needed in the electrode fabrication process because of the highly porous nanostructured carbon materials, increasing the manufacturing cost and decreasing the energy density. Thus, the porosity and taping density should be well balanced. To achieve high volumetric energy density at a low cost, future research can focus on forming graphene-based 3D composites by using capillary drying or rapid drying processes ,132.(5)Advanced electrolytes with a wide working voltage and high safety are also needed. Currently, typical LICs commonly adopt organic electrolytes to achieve a high operation voltage. However, they suffer from safety issues associated with volatility, flammability and toxicity. Hence, other novel electrolytes have been explored. For example, ionic liquids are regarded as a promising alternative to the organic electrolyte owing to their large working voltage, high conductivity and excellent thermal stability without risk of catching fire ,138. Rec(6)The decomposition of electrolytes should not be ignored. Generally, electrolyte decomposition on the cathode and anode takes place during the charge/discharge process, especially at a high working voltage, resulting in gas emission, impedance increase and low energy conversion efficiency. At the anode side, this phenomenon can be largely restrained by forming a stable solid–electrolyte interface (SEI) during the first several cycles. However, an effective strategy to suppress the electrolyte decomposition at the cathode side is still absent . Fortuna(7)Besides the above discussion, other critical issues should also be solved before industrial-level production and widespread applications. First of all, feasible pre-lithiation technology should be developed because the anode, especially nanostructured materials with a large SSA and rich porosity, would consume a large amount of lithium ions when forming a stable SEI ,149. Wel(8)Additionally, considering the limited and uneven distribution of lithium resources, other metal-ion capacitors are drawing increasing attention and have recently become the research hotspot. In particular, monovalent ion systems  are the most promising alternatives to LICs because they have a similar cell configuration and energy storage mechanism as well as abundant resources ,157. HowNevertheless, the performance of the current graphene-based capacitor-type electrodes is still far from the practical requirements. Moreover, other remaining challenges related to battery-type anodes, the production of graphene-based materials, volumetric performance, electrolytes, performance imbalance between the anode and cathode and pre-lithiation technologies should be given more attention, too. Thus, the following several aspects should be considered to overcome the present challenges and to realize the commercialization of LICs:In conclusion, LICs have witnessed tremendous progress during the last decade, especially in electrode materials. Their development steps are speeding up and large-scale application will be realized in the near future. Without a doubt, graphene-based nanomaterials could play a vital role in achieving high performance due to their outstanding electrochemical properties.


In the proposed structure, a refractive index grating is formed at the subwavelength scale due to the periodical distributions of amorphous and crystalline states, and the structure is intrinsically flat. The numerical simulation shows that nearly 100% absorption can be achieved at the wavelength of 1550 nm, and the Q factor is more than hundreds due to the loss-less value of Sb2S3 in the near-infrared region. The absorption spectra can be engineered by changing the crystallization fraction of the Sb2S3 as well as by varying the duty cycle of the grating, which can be employed not only to switch the resonant wavelength but also to achieve resonances with higher Q factors. This provides a promising method for realizing integrated graphene optoelectronic devices with the desired functionalities.Graphene absorbers have attracted lots of interest in recent years. They provide huge potential for applications such as photodetectors, modulators, and thermal emitters. In this letter, we design a high-quality (Q) factor resonant graphene absorber based on the phase change material Sb Graphene absorbers have attracted lots of interest in recent years ,2,3. ThePhase change materials (PCM), such as ong time ,31,32, song time , dynamicong time ,35,36, bong time , and ligong time ,39,40,41ong time ,43. Elecong time . HoweverIn this study, we propose a high Q rewriteable resonant graphene absorber with the phase change material antimony trisulphide . Since our structure is assumed to be “infinitely extending” in the y direction, we use a two-dimensional model for simulations (x–z plane). We used Floquet periodic boundary conditions in the x-direction, and port boundary conditions at the top and bottom of the model along the z-direction. In the simulation, urements , and thety model :(1)σω=σid is the thickness of graphene. For the graphene monolayer, we have Here, graphene . Figure f = 0.5 to f = 0.1, the resonance wavelength shifts from 1547.9 nm to 1542.4 nm and the maximum resonant absorption decreases from 99.83% to 40.88%. At the same time, the spectral linewidths (FWHM) decrease from 2.4 nm to 1.4 nm, corresponding to an increase of the Q factor from 644 to 1101 (Q = The excitation of the guided mode resonance can be controlled by changing the geometric parameters of the structure (such as period and duty cycle), as mentioned above. We now fix the period of the grating, and tune the absorption spectra by changing the duty cycle. As shown in the e theory , that is (γ + α) , the FWHf is reducing, and it can be avoided so long as the effective absorption rate of graphene f = 0.1 and f = 0.2 as the example, as shown in the f = 0.1 and f = 0.2 are 0.23 nm and 0.88 nm, corresponding to high Q of 6726 and 1760, respectively, which is the consequence of the decrease of the mode leakage rate This type of mismatch results from the decrease of the mode leakage rate f = 0.5 and vary the crystallization fraction of A previous work has demonstrated that there is an intermediate state of of Sb2S3 . The effmix rule :(3)εeffλTo investigate the influence of the boundary between amorphous and crystalline PCM, we also set a linear graded-index with the width of 100 nm at each boundary between amorphous and crystalline  see the c.f = 0.1 and a spacing layer between the phase change material-based grating and graphene to reduce both the coupling rate and the absorption rate. This type of high Q resonant of two-dimension materials of the integrated phase change metadevice can also be applied to other atomical materials, such as In all, we have proposed a type of subwavelength resonant graphene absorber based on the phase change material witching ,55, couliderable . This priderable .


The degree of doping increased with DUV exposure time. However, n-type doping by DUV in vacuum reached saturation after 60 min of DUV irradiation. The p-type doping by DUV in air was observed to be quite stable over a long period in a laboratory environment and at higher temperatures, with little change in charge carrier mobility. The p-doping in pure O2 showed ~15% de-doping over 4 months. The n-type doping in pure N2 exhibited a high doping effect but was highly unstable over time in a laboratory environment, with very marked de-doping towards a pristine condition. A lateral pn-junction of graphene was successfully implemented by controlling the radiation environment of the DUV. First, graphene was doped to n-type by DUV in vacuum. Then the n-type graphene was converted to p-type by exposure again to DUV in air. The n-type region of the pn-junction was protected from DUV by a thick double-coated PMMA layer. The photocurrent response as a function of Vg was investigated to study possible applications in optoelectronics.The electronic properties of single-layer, CVD-grown graphene were modulated by deep ultraviolet (DUV) light irradiation in different radiation environments. The graphene field-effect transistors (GFETs), exposed to DUV in air and pure O There are several methods to attain single-layer graphene, such as mechanical exfoliation of graphite, epitaxial growth of graphene, and chemical vapor deposition (CVD) on a metal (Cu or Ni) foil substrate ), as shown in energy band diagram in  surface . The mobg are shown in CNP in sample-2 was observed around 5 V which readily shifted towards negative gate voltages (−14 V after 60 min-DUV) with increased treatment time, indicating n-type doping. Sample-2 exhibited a saturation point for n-type doping behavior after 60 min of DUV exposure. − or H2O−) by hole recombination (h+ + O2− = O2) and releases electrons. With small changes in carrier mobility and no major changes in the graphene structure, these liberated electrons induce an n-type doping activity in graphene [F is increased above ED, as shown in the energy band diagram in g for sample-3 (DUV irradiation in pure O2), illustrating the p-type doping in graphene for 60 min of exposure time. The photo-assisted oxidation by DUV irradiation in a pure O2 environment induces p-type doping to the graphene. The transfer characteristics of sample-4 (DUV irradiation in pure N2) are shown in 2 environment. The shift in VCNP for sample-4 (VCNP = ~−17.8 V) was higher compared with sample-2 (VCNP = ~−13.7 V) for 60 min of DUV exposure time. The N2 gas in the presence of DUV irradiation dissociates into atoms which are absorbed on the surface of the graphene. These N2 atoms react with the oxygen atoms present on the surface of the graphene and produce O2 molecules that are removed [2 atoms under DUV attach to the graphene surface and become the major source of electrons, inducing higher n-type doping. The transfer characteristics for sample-5 were investigated for 60 min DUV in pure N2, followed by 60 min irradiation in vacuum, as shown in CNP = −24.6 V). Under further DUV exposure in vacuum, the N2 atoms attached to the graphene surface induce a further doping effect. Both N2 atoms and larger exposure times are responsible for a higher n-type doping effect. CNP (CNP after DUV Doping—CNP before DUV Doping) and VCNP for DUV doping in different irradiation environments. The ∆VCNP shows a higher shift in the CNP position for the air condition in p-type doping, and for pure N2 followed by the vacuum condition in n-type doping, for 60 min of DUV exposure time.The electric transport characteristics for sample-2 (DUV irradiation in vacuum) with resistivity as a function Vgraphene . This do removed ,31,32,393P) atoms dissociated from oxygen in air under DUV were attached to the most stable bridge sites of graphene, exhibiting stable p-type doping behavior [CNP = 13.7 V to 11.3 V. It was predicted that the oxygen from air in the ambient laboratory conditions would attach to the graphene surface over time, inducing a de-doping effect. The oxidation of the graphene layer over the period is the main reason behind the de-doping effect observed in graphene. 2 molecules which were unable to find stable bridge sites would detach from the graphene surface. The doping stability of sample-4 was investigated over 4 months, exhibiting a high de-doping effect of around 54%, as shown in 2 atoms attached to the graphene surface, inducing n-type doping, were detached over time because of weak dangling bonds. The oxygen from the ambient air also reacted with the graphene, inducing a large de-doping effect in n-type behavior because of the oxidation. 2 atoms attached to the graphene surface with weak dangling bonds detached and the O2 atoms from the ambient air reacted, resulting in very high de-doping towards a pristine state. Thus, from our studies, we observed that p-type doping stability in sample-1 was very high compared to sample-3, which exhibited a small de-doping effect in sample-3 over time. The n-type doping stability in sample-2 with little de-doping was considerably better compared to sample-4 and sample-5 which showed a large de-doping effect over time.The stability of the doping level of graphene is an important factor for its application in electronic devices. behavior . Figure CNP, similar to pristine graphene. No change in electronic properties and the doping effect in graphene by DUV irradiation were observed for the device coated with a thick PMMA layer. As previously reported, the transmission of light through the PMMA layer decreases when the thickness of the film is increased [CNP positions for pristine graphene, single layer PMMA (1274 nm), and double-layer PMMA (2548 nm) coated graphene, respectively. It can be readily observed that sample-7, with a thicker layer of PMMA (2548 nm), showed a negligible shift in the CNP position for different DUV exposure times. Furthermore, the effect of DUV light irradiation on graphene, covered with PMMA, was investigated by assessing the transfer characteristics of the device for different DUV treatment times, as shown in ncreased ,43. The d as a function of Vg in sample-10 for the pn-junction, p, and n regions of the device. An optical image of the device with defined n, p, and pn-regions is shown in the inset of CNP of around −8 V. The red transfer curve exhibited the counter doped p-type behavior of the graphene with a VCNP position at around 30 V f. On investigation of the transfer characteristics of the pn-region, it exhibited two distinct CNPs at negative and positive Vg, each corresponding to the n-type and p-type doping effect in graphene, shown by the black transfer curve in d-Vd characteristics of the n, p, and pn-regions at different Vg with Id sweep from −2 V to 2 V, are shown in d on positive gate voltages for n-type and a decrease in Id on positive gate voltages for p-type regions, respectively. d-Vd characteristics of the n, p, and pn-regions at different Vg with Id sweep from −2 V to 2 V, are shown in d on positive gate voltages for n-type and a decrease in Id on positive gate voltages for p-type regions, respectively. The DUV induced n and p-type doping are reversible under controlled conditions ,22,25,30p) (the difference of Id under light and Id without light illumination) as a function of Vg was investigated for graphene pn-junction devices using an ultraviolet light (λ = 365 nm and 350 µWcm−2 intensity) source (Mightex P/N WLS-22-A light source) as shown in d of 1 V, is shown in p for the pn-junction was readily enhanced as compared to the p and n region of the graphene because of an increase in the photocarrier’s generated built-in potential created by the formation of the pn-junction [g. The Ip curve depicts a positive photocurrent at negative Vg which undergoes a sign reversal and becomes negative for positive Vg, which is consistent with previously reported studies [p can be modulated by Vg [++p, p+n, and n+n+, respectively [n-type and CNPp-type) formed by the hole and electron conduction regions confirm the formation of the pn-junction in the graphene single channel [2 led to an increase in conductivity, and the electric field effect in the graphene was enhanced due to applied gate voltages resulting in increased mobility, as also observed in other semiconducting 2D materials [g and can modulate the polarity and magnitude of Ip with applied gate voltages [p was observed around a Vg of −20 V outside the pn-junction region of the device which usually has the maximum potential difference of the p and n regions. This can be explained by the fact that light was illuminated on the whole device which includes not only the p+n region but also the metal and interface junction in p++p and n+n+ regions of the graphene [The photocurrent . The shift in G and 2D peaks of Raman spectra towards higher wavenumbers and the shift of CNP towards positive Vg values in transfer characteristics confirmed the p-type doping for graphene devices with an increase in DUV exposure time in air and pure O2 environments. The p-type doped graphene exhibited high stability over time with a minor de-doping (14%) effect in the pure O2 environment. The shift in G and 2D peaks towards smaller wavenumbers in Raman spectra and the CNP shift towards negative gate voltages in transfer characteristics confirmed the n-type doping in graphene exposed to DUV irradiation in vacuum and pure N2 environments. The n-type doping with a small de-doping (16%) effect for the device exposed in vacuum was considerably better compared to highly unstable n-type doping with a large de-doping (54% and 90%) effect over time for devices exposed to DUV in pure N2 and pure N2 followed by a vacuum environment. The thick PMMA (2548 nm) layers reduced the DUV irradiation effect on graphene by increased light absorbance and reduced light transmittance. A lateral pn-junction in a single graphene channel was fabricated in a controlled DUV irradiation environment and specified doping in selected regions with and without PMMA coating. The back gate-dependent transfer and Id-Vd characteristics for n, p, and pn regions of the device validate the process to be a suitable technique to alter the electronic properties of graphene, without varying the physical and chemical properties of graphene. The results of photo-response current measurement as a function of back-gate voltage showed increased photo-response of the device because of increased field-effect mobility in the graphene channel. This study has presented a possible photo-assisted technique under defined conditions for the modification of the electronic properties of graphene for potential future application in electronic and optoelectronic devices.In this study, we thoroughly investigated the DUV-irradiation-induced doping effect in CVD-grown graphene, under controlled irradiation environments (air, vacuum, pure O


This work introduces a novel humidity sensor based on a nanocomposite material comprising graphene decorated with three-dimensional flower-like structures of zinc oxide (Gr/3D–ZnO) fabricated via a hydrothermal method with various weight percentages of graphene. The surface structure and morphology of the Gr/3D–ZnO nanocomposite were analyzed using XRD, EDS, SEM, TEM, and Raman spectroscopy. The influence of humidity on the electrical properties of the nanocomposite was also investigated. Experiment results revealed that the nanocomposite with 70 wt% of graphene provided high sensitivity (S = 446) with rapid response times (120 s) and recovery times (160 s). These results demonstrate the excellent potential of the proposed Gr/3D–ZnO nanocomposite in monitoring atmospheric humidity. A discussion on the mechanism underlying the effects of humidity on the Gr/3D–ZnO nanocomposite is also provided. Atmospheric levels of water vapor  can profoundly affect electronic devices, meteorological phenomena, agriculture, manufacturing, and food storage . Efforts2 nanopowders [3 nanosheets [2O3 nanopowders [2 nanorods [2 nanofibers [2 bonded carbon atoms, has a large surface to volume ratio and excellent conductivity [Numerous types of humidity sensors have been developed using resistive ,5 and caopowders  and nanoopowders , ZnO nanopowders , WO3 nannosheets , Fe2O3 nopowders , graphenopowders , organicopowders , ZrO2 nananorods , and NiOnofibers . Among tnofibers . ZnO cannofibers , nanorodnofibers , nanoshenofibers , nanoparnofibers , nanofibnofibers , hollow nofibers , and nannofibers . Despitenofibers . Nonethenofibers . Graphenuctivity ,35,36, wuctivity ,39,40,41uctivity ,43. The uctivity ,45.Our objective in this study was to fabricate a sensor based on a nanocomposite material comprising graphene decorated with three-dimensional flower-like structures of zinc oxide (Gr/3D–ZnO). The surface structure and morphology of the Gr/3D–ZnO nanocomposite were characterized using XRD, EDS, SEM, TEM, and Raman spectroscopy. We also investigated the influence of humidity on the electrical properties of the nanocomposite. The completed humidity sensor exhibited ultra-high sensitivity with fast recovery and response times over a broad range of relative humidity (RH) levels.3)2·6H2O, 98%), anhydrous alcohol , L-histidine , urea ((NH2)2CO, 99.5%), and polyvinyl alcohol  were purchased from Sigma-Aldrich Co., Inc.Commercial graphene film of high purity (>99%) was purchased from UniRegion Bio-Techn  and Sigma–Aldrich Co., Inc. . Zinc nitrate hexahydrate . The crystal structure of Gr/3D–ZnO was characterized using an XRD-6000 Shimadzu X-ray diffractometer with Cu Kα radiation of 1.5405 Å at 40 kV and 30 mA between 10° and 80° (2θ) at intervals of 2°/min. Infrared spectra were measured using an Agilent Cary spectrophotometer. The characteristic Raman spectrum of the Gr/3D–ZnO nanocomposite was measured at RT under excitation from a laser source at a wavelength of 532 nm .2), whereupon the chips were heated to 80 °C and held at that temperature for 0.5 h before undergoing calcination at 400 °C for 2 h.A solution of 10% PVA was added to promote the binding of the composite. A pair of comb-like gold electrodes were applied to an alumina substrate via dip-coating  and Rh is the resistance under a specific level of humidity [The experiment setup used to assess the performance of the humidity sensor is described in our previous work . Brieflyhumidity . The humHumidity hysteresis error (H) was calculated using the following equation:e output . The rese output . RH was −1 and 1568 cm−1) were presumably due to in-plane bond stretching of sp2 hybridized carbon atoms and the corresponding combinational modes and overtones [−1 are the vibrational modes of ZnO [As shown in vertones ,51. The s of ZnO . The Gr/We assessed the sensitivity of Gr/3D–ZnO nanocomposite materials  to humidity based on impedance measurements obtained using AC voltage (1V) at a frequency of 1 kHz. As shown in Humidity hysteresis is an important factor in evaluating the reliability of humidity sensors . As showResponse and recovery times largely determine the practical applicability of humidity sensors. As shown in 12%/R90% = 446). The response to other gas species was as follows: CO (1.55), NH3 (1.41), NO2 (1.36), and NO (1.18). Overall, the Gr/3D–ZnO nanocomposite exhibited excellent selectivity for humidity.Selectivity is another crucial parameter in assessing the performance of humidity sensors. 2O or H3O+ was on the discontinuous water layer was difficult [2O or H3O+. Grotthuss and Casalbore-Miceli et al. outlined an ion transfer mechanism involving the transfer of H2O or H3O+ on serial water layers: H2O + H3O+ → H3O+ + H2O [At low relative humidity (RH), the probability of contact between water molecules and Gr/3D–ZnO nanocomposite particles was low, so only the outer particles came into contact with the water molecules, as shown in ifficult . TherefoO+ + H2O ,60. ThisIn this work we have succeeded in fabricating Gr/3D–ZnO nanocomposites via a hydrothermal process to create a novel low-cost humidity sensor based on Gr/3D–ZnO nanocomposite material. Experiment results revealed that the nanocomposite with 70 wt% graphene provided a high sensitivity (S = 446) with rapid response times (120 s) and recovery times (160 s). The highest humidity hysteresis error was only 2.32% over a wide range of RH values. These results demonstrate the excellent potential of the proposed Gr/3D–ZnO nanocomposite for the development of low-cost sensors to monitor atmospheric humidity.


We challenged four big brown bats to maneuver through abrupt turns in narrow corridors surrounded by dense acoustic clutter. We quantified bats' performance, sonar beam focus, and sensory acquisition rate. Performance was excellent in straight corridors, with sonar beam aim deviating less than 5° from the corridor midline. Bats anticipated an upcoming abrupt turn to the right or left by slowing flight speed and shifting beam aim to “look” proactively into one side of the corridor to identify the new flightpath. All bats mastered the right turn, but two bats consistently failed the left turn. Bats increased their sensory acquisition rate when confronting abrupt turns in both successful and failed flights. Limitations on biosonar performance reflected failures to switch beam aim and to modify a learned spatial map, rather than failures to update acquisition rate.  •Echolocating bats use sonar to identify flightpaths through dense, cluttered scenes•Bats learn new flightpaths by switching beam aim before encountering obstacles•Bats see their environment in depth Biological Sciences; Zoology; Animals; Ethology Eptesicus fuscus, modifies the direction and timing of its biosonar calls when flying through a cluttered environment requiring maneuvers through tight turns. As in natural clutter, multiple objects in this environment are located nearer than the upcoming opening in the scene, so the bat has to peer through a screen of echoes to discern the place where a turn will be necessary to maintain the flightpath.Echolocating bats intercept flying prey and navigate through their environments using information provided by reflected echoes. To identify obstacles and open flightpaths, they actively modulate the number, temporal patterning, and spatial direction of their biosonar calls . Many baBig brown bats have a versatile biosonar system. They capture prey in open spaces as well as on the ground and in or near vegetation; they fly above the forest canopy, between gaps in foliage, and within caves and other roosting spots . Their sBesides changing beam aim, big brown bats also modify their sensory acquisition rate when flying in cluttered environments compared to flying in the open . In the One issue with the hypothesis that changes in pulse timing reflect the bat's own interpretation of an acoustic scene as “easy” or “difficult” is that in many flight and obstacle avoidance experiments, big brown bats exhibit excellent performance, with few or no errors . They naFour big brown bats were challenged to fly through a 40-cm-wide corridor surrounded by an array of 217 hanging plastic chains that produced intense, extended echoes  did not differ significantly from that in the Straight condition (pairwise comparisons: p = 0.096). All four bats, regardless of whether they had previous laboratory experience in flying amid clutter, experienced a large drop in performance on the first day of the Right Turn condition, with success rate ranging from 0% to 69% (M = 45.1%). Success rate reached M = 84.8% within the first 3–4 days of this condition . ExperieSuccess rate in the Left Turn condition differed considerably among bats. Bat 1 and Bat 2 improved their performance over flight days, with success rate increasing from M = 26.5% on the first day of flights to M = 100% on the last day of flights. On the other hand, neither Bat 3 nor Bat 4 completed the task successfully, with success rates of 0% on both the first and the last day of flights.= 0.90, respectively]. Conversely, Bat 3's performance differed significantly across conditions . This bat performed equally well in the Straight and Right Turn conditions (pairwise comparisons: p = 0.85), but significantly worse in the Left Turn compared with Right Turn condition (pairwise comparisons: p < 0.001). Bat 4's performance also differed significantly across conditions . This bat performed similarly in the Straight and Right Turn conditions (pairwise comparisons: p = 0.36), but significantly worse in the Left Turn compared with the Right Turn condition (pairwise comparisons: p < 0.001).We statistically analyzed performance on a bat-by-bat basis. Bat 1 and Bat 2 both showed similar performance across conditions . Consistent with the data from successful flights, the majority of SSGs in failed flights  = 2,825, p < 0.001; Bat 4: Right versus Left, χ2 = 1,247, p < 0.001], with the difference due to production of more SSGs of 3–8 pulses.We calculated the proportions of SSGs in successful and failed flights in all three flight conditions. The non-linear way in which bats modify the timing of their calls is also visualized by plots of the distribution of pre-IPI values of every call against the corresponding post-IPI values . These pThis experiment required big brown bats to navigate down narrow corridors and through sharp 90° turns embedded in intense acoustic clutter produced by a dense array of surrounding chains. We hypothesized that bats would find this task challenging, and our results support this hypothesis. Bats were able to fly down Straight corridors with a mean success rate of 94% (four bats). This high success rate is consistent with those found in other experiments that also challenged bats to navigate narrow straight or curved corridors surrounded by various densities of clutter  to achieve final success. In the Right Turn condition, performance improved for all bats, reaching 100% correct in one animal, as they gained more experience with the flightpath over experimental days. After initial failures, two bats were able to achieve a success rate of 100% in the Left Turn condition; however, two other bats were unable to master that condition over the duration of the experiment, even with practice. These large individual differences indicate that the Left Turn was not intrinsically more difficult due to its closer proximity to the flight room wall. Moreover, bats' previous experience with flying down narrow corridors does not explain this individual variability; the same bat that achieved a high level of performance in earlier corridor experiments  had a suA previous experiment quantifying beam aim required big brown bats to fly through an open room or through openings in mist nets to catch a tethered insect prey . In the We hypothesized that bats flying toward abrupt 90° turns would aim their sonar beam in the direction of these turns before reaching them. Our results support this hypothesis. Bats that were able to navigate in the Turn conditions shifted their beam in the appropriate direction between 30 and 65 cm (224–359 ms) before reaching the turns. These anticipatory times are at the upper edge of the time range quantified by Consistent with the formation of a spatial map , bats adA strategy of focusing the center of the sonar beam on the nearest obstacle preventing a turn is an adaptive strategy that allows bats to localize and navigate tight spaces, such as gaps in foliage, more accurately. The center of the beam provides the highest signal-to-noise ratio (SNR) for echoes from any potential obstacle compared with the periphery . FocusinChanging beam aim based on an acquired spatial memory of the flightpath is beneficial to bats that must navigate tight spaces, allowing them to collect as much information as possible about upcoming obstacles in the direction of flight. However, an early proactive movement of the beam may make the bat less able to adapt to abrupt changes in the environment, even after multiple encounters with a new flightpath. Bats may incur a perceptual cost by shifting their acoustic gaze too early; a portion of their approach to the turn is spent echolocating off-axis from the area into which they will fly before entering the turn. Any echoes received from this immediately upcoming area would be perceived as clutter and perceptually blurred , making Insectivorous echolocating bats increase their sensory acquisition rate as background clutter becomes physically closer or denser, and as they approach a landing surface or wall . The chaWe predicted that more calls would be emitted as SSGs in the more difficult Turn conditions, and the data support this prediction. These data are also consistent with previous work showing more call clustering in tasks presumed to be more perceptually difficult . SSG proThe visualization of pre/post-IPI distributions for individual bats indicates that individual bats use unique patterns of call timing in order to solve the same perceptual task, and that these unique patterns within individuals are consistent across changes in the surrounding environment. Indeed, the pre-IPI to post-IPI distributions in failed flights were similar to those in successful flights by the same individual. Variability in task performance among bats is not attributable to changes in the temporal patterns of sensory acquisition, but rather due to individual differences in the spatial sampling strategies employed.Together, these findings paint a picture of how bats modify their biosonar behaviors to perceive upcoming obstacles (chains), adjust their calling patterns to avoid these obstacles, and adapt their beam aim to drastic changes in the spatial environment. Bats localizing and navigating a gap within dense acoustic clutter focus their calls on the nearest obstacle defining the edges of the gap in order to best localize the relatively small gap. In effect, they make sonar “looks” into the surrounding clutter to identify upcoming openings amid multiple nearer objects and echoes arriving earlier than the absence of echoes signifying the opening. In this way, they can identify an open flightpath. These proactive beam aim changes are tightly integrated with a spatial memory of the bat's environment, which is built up with experience. This is best exemplified by the persistence of some bats in aiming their calls in the direction required by a previous condition, even after substantial experience in a new spatial layout. This spatial memory, required for successful navigation, may also inhibit the ability of bats to adapt to sudden changes in the environment. Bats that were able to unlearn a pattern of beam aim were more successful in navigating a novel, orthogonal flightpath compared with other bats that became “stuck” in a learned pattern of beam aim. These differences between individual bats could lead to significant differences in their ability to navigate and survive in volatile, physically changing environments. We conclude that failures in navigating complex flightpaths are due to the bat being unable to alter its beam aim, not to an inability to change its sensory acquisition rate. Final success reflects the bat's ability to form a new spatial map of its environment .One issue raised by this experiment concerns the poor performance of two of the four bats in the Left Turn condition. It is possible that the Left Turn was more challenging because it was closer to the flight room wall. The simultaneous use of the flight room for other experiments prevented locating the experimental corridor in a more symmetrical manner. The better performance of these two bats in a Reversed Right Turn condition suggests that proximity to the wall did not affect their performance; rather, they did poorly in the Left Turn because they became “stuck” in aiming their beam toward the right. However, this new condition could only be run for one day, because of the bats' refusal to continue flying. These two bats were in good health during the experiment, and remained so for one year after its end. Finally, although the LMM model controlled statistically for the fixed order of conditions, future experiments should randomize conditions. It is also more difficult to quantify changes in temporal patterning that may have occurred in response to spatial changes, as time spent in the experiment is a confounding factor for all bats.Andrea_Simmons@brown.edu).Further information and requests should be directed to and will be fulfilled by the corresponding author, Andrea Simmons (Please contact the corresponding author.https://doi.org/10.26300/0mpw-9f40.Original data have been deposited in the Brown Digital Repository: All methods can be found in the accompanying


American Indians (AI) have the highest smoking rates and lowest quit rates of any racial/ethnic group in the U.S. Researchers and community members from the American Indian Health Research and Education Alliance (AIHREA) created and evaluated a culturally-tailored smoking cessation program, All Nations Breath of Life (ANBL) as a recruitment tool for smoking cessation programs among AI. To increase enrollment in ANBL, AI smokers were approached at cultural events and asked to attend a 30-minute educational session . Tele-video (30%) and in-person (9%) session participants were recruited into ANBL. Pre- and post-tests showed participants in both sessions demonstrated increased motivation and confidence to quit smoking but significant differences were present in both sessions (p < 0.0001). Results indicate that theoretically guided and culturally tailored education sessions are viable approaches to educate and recruit underserved populations into programs that promote smoking cessation. Commercial tobacco usage rates among American Indians (AI) are the highest when compared to all other racial and ethnic groups in the U.S. . AI haveTo better understand how to bolster AI participation into smoking cessation programs, we explored the utility of culturally tailored educational sessions as a recruitment tool. Theoretically guided and culturally tailored tobacco education sessions delivered by AI research staff provided participating AI communities with health information about the consequences of cigarette smoking. The team subsequently used the tobacco education sessions to recruit participants based on community engagement principles and Health Belief Model (HBM) constructs. Information gathered through this process provided a framework to influence and motivate individuals to quit smoking through a culturally appropriate and relevant program.From August 2011 to November 2012 American Indian Health Research Education Alliance (AIHREA) team members recruited AI smokers, 18 years of age or older N=276) for participation in tobacco education sessions (All Nations Breath of Life) [ for partRecruitment for the in-person education sessions was conducted on-site by AI team members through announcements at event venues, word of mouth, and personal invitation. These methods yielded 179 participants for 12 in-person sessions. Recruitment for the tele-video sessions was conducted in a similar fashion but incorporated the use of AI specific listservs and flyers and yielded 97 participants for the 12 tele-video sessions.An AI team member led the sessions (n=24) which lasted for 30 minutes. Prior to the start of each session, participants answered demographic and health-related questions, as well as a 12- question pre-test about their recreational smoking health knowledge. At the end of the session, participants took a 10-question post-test that mirrored the pre-test . ParticiThe education sessions were interactive; participants were encouraged to ask questions and to make comments throughout the presentation. The educational material was delivered orally, a format preferred by AI participants in previous research conducted by the team. Each presenter was given a detailed outline of information to cover and then follow during all sessions. Given that the sessions were interactive and participants could ask questions and make comments, there were some differences among the discussions; however, the educational material was presented uniformly across sessions.AI members of the research team conducted tobacco education sessions throughout regional AI community and cultural events. Throughout the sessions the team relayed information about health consequences of cigarette smoking, environmental tobacco smoke, and third hand smoke. The facts provided were specific and culturally tailored to AI populations and guided by components of the Health Belief Model . HBM conp < 0.01). Participants attending the in-person sessions had more significant partners/spouses who “currently smoke” . Participants in the in-person sessions smoked less days in the prior 30 days  and had been smoking for less years at their current rate  than participants in the tele-video sessions. Participants in the in-person sessions also had lower dependence on nicotine, measured by the Fagerstrom Test for Nicotine Dependence , but were more likely to use other forms of tobacco . Participants in both groups were similar across other variables (The average age of participants for the in-person session was 32 compared to 41 for tele-video sessions (ariables .(p < 0.01). Further, participants who attended either session demonstrated significant increased confidence to quit smoking (p=0.04 for in-person participants and p < 0.01 for tele-video participants). Knowledge scores of tobacco use and side effects of tobacco usage significantly increased from pre- to post-tests in both in-person (p < 0.01) and tele-video (p < 0.01) sessions.Pre- and post-test data for motivation and confidence to quit, and tobacco knowledge, were collected during both the in-person and tele-video sessions. Similar results were found in both arms. Participants who attended either session demonstrated an increased motivation to quit smoking; this increase was significant among in-person session participants p < 0.01), but not for motivation or confidence. Similarly, overall pre- and post-test score comparisons were significant, including motivation to quit smoking , confidence to quit smoking , and knowledge .Significant differences were found in total knowledge gains pre-test to post-test for in-person participants compared to tele-video participants  after attending one of the education sessions. More than 9 % of the participants who attended an in-person session and 30% of the participants who attended a tele-video session were recruited into ANBL, even though all participants entered the sessions not planning to enroll in a quit smoking program.Results suggest that education sessions theoretically guided by the HBM and community engagement principles were an effective way to inform AI smokers about smoking-related health outcomes and other tobacco facts specific to AI. This strategy also shows promise as a successful recruitment tool for AI programs similar to the All Nations Breath of Life (ANBL) smoking cessation program in the Midwest. While participants in both sessions experienced an increase in knowledge, the in-person sessions showed a greater impact on improved total knowledge. There was a significant increase in motivation and confidence to quit smoking for both sessions. Here, theoretically guided education sessions helped increase motivation and confidence to quit smoking among AI in this sample. This suggests that education sessions based on CBPR principles and guided by constructs of the HBM may be tools to use in recruitment and tailoring specific information. There is utility in applying theoretically driven health education that accounts for individual perceptions and beliefs. This approach may prove beneficial in demystifying interventions and health promotion programs targeted to minority, underserved and vulnerable populations. Here too, CBPR principles where members of AI were involved helped to strengthen recruitment efforts into smoking cessation programs.In this study, the team was able to compare in-person versus tele-video tobacco education sessions to determine which was more successful at 1) improving participants’ tobacco knowledge and motivation to quit smoking, and 2) enrolling participants into the ANBL culturally tailored smoking cessation program. Present findings indicate that age, smoking status of significant partner/spouse, number of children living with a participant, number of days cigarettes were smoked in the past 30 days, years smoked at current smoking rate, nicotine dependence, and recreational use of other tobacco products may be important correlates of whether an individual participated in an in-person or tele-video tobacco education session. It is also possible that recruitment methods or locations for each type of session determined the type of individual to participate in that type of session.Participants from both types of education sessions were recruited into the ANBL smoking cessation program . AI smokers historically have lower quit rates and are less likely to enroll in smoking cessation programs than members of other racial/ethnic groups. Fu and colleagues .Other studies have reported factors that influence the success of study recruitment and retention, such as building rapport  increasiThere were some limitations with the study that included sample selection process and managing recruitment of individuals into education sessions near the closing of the ANBL program. All participants included in the study self-identified as smokers however it is possible that not all participants were smokers. Participants also were recruited for the sessions (in-person vs. tele-video) by team members and were not randomized into sessions. In addition, the participants were recruited throughout the region and thus there may be variation in other AI communities where geographical, historical, and sociocultural characteristics differ. The sample did represent, however, a heterogeneous mix of tribes and localities  and team members conducted purposive recruitment among AI community members to achieve a representative number in both in-person and tele-video sessions. Finally, recruitment for the ANBL effectiveness trial ended before the completion of the planned education sessions. The team chose to finish the scheduled education sessions although recruitment for the ANBL program had ended and offered these individuals an opportunity to participate in future programs. Therefore, it is possible that additional participants could have been recruited into the program. Future studies are needed to further test tobacco education sessions as a recruitment tool and the impact on health behavior . GatheriA major strength of this study was the use of education sessions (both in-person and tele-video) in recruiting for a culturally tailored quit smoking program. This study explored the impact of education sessions on motivation, confidence, knowledge and the utility in recruiting AI into a smoking cessation program. Pinpointing these individual-belief factors among AI members increases the potential to identify motivators and facilitators for smoking cessation behavior and also cues to action. These factors also may help health promoters to innovatively shape education via recruitment processes that lead to increased beneficial health promotion programming among AI populations.


Sarcoidosis is a granulomatous systemic disease of unknown etiology. Mononuclear cells such as macrophages or lymphocytes in lung tissue and hilar or mediastinal lymph nodes have been recognized to play an essential role in granuloma formation in pulmonary sarcoidosis. Peripheral blood mononuclear cells (PBMCs) consist of several immunocompetent cells and have been shown to play a mechanistic role in the pathogenesis of sarcoidosis. However, the genetic modifications that occur in bulk PBMCs of sarcoidosis remain to be elucidated.This study aimed to explore the pathobiological markers of sarcoidosis in PBMCs by comparing the transcriptional signature of PBMCs from patients with pulmonary sarcoidosis with those of healthy controls by RNA sequencing.n = 8) and healthy controls (n = 11) from August 2020 to April 2021, and RNA sequencing was performed with the PBMC samples.PBMC samples were collected from subjects with pulmonary sarcoidosis with no steroid/immunosuppressant drugs -1 and IFN-γ, regulation of IL-6 production, IL-8 secretion, regulation of mononuclear cell migration, and response to lipopolysaccharide, were involved. Enrichment analysis of the KEGG pathway indicated the involvement of tumor necrosis factor (TNF), toll-like receptor signaling, IL-17 signaling pathways, phagosomes, and ribosomes. Most of the genes involved in TNF and IL-17 signaling pathways and phagosomes were upregulated, while most of the ribosome-related genes were downregulated.The present study demonstrated that bulk gene expression patterns in PBMCs were different between patients with pulmonary sarcoidosis and healthy controls. The changes in the gene expression pattern of PBMCs could reflect the existence of sarcoidosis lesions and influence granuloma formation in sarcoidosis. These new findings are important to strengthen our understanding of the etiology and pathobiology of sarcoidosis and indicate a potential therapeutic target for sarcoidosis. Granulomas consist of monocyte-derived epithelioid and giant cells encircled by various immune-competent cells such as CD4 + helper T (Th) cells, CD8 T cells, fibroblasts, regulatory T cells, and B lymphocytes -2 and IFN-γ  comprise immunocompetent cells, which are mainly classified into two cell types: monocytes and lymphocytes. Monocytes are defined as CD14in PBMCs , which cal roles . As suchOmics is a recently developed analysis method that encompasses genomics, epigenomics, transcriptomics, proteomics, and metabolomics, and has already been widely used to understand polygenic and phenotypically diverse diseases. In particular, transcriptomics has also been applied to understand the pathogenesis of sarcoidosis at the levels of PBMCs, monocytes, regulatory T cells, and single cells of PBMCs, to explore specific genetic expressions of mRNAs or microRNAs that might explain disease progression and distinguish it from other diseases , 9.A previous study showed that gene expression in PBMCs was different between sarcoidosis patients and healthy controls ; howeverTherefore, this study aimed to explore the pathobiological significance of PBMCs in sarcoidosis by comparing the transcriptional signature of PBMCs from healthy controls with that from pulmonary sarcoidosis subjects not receiving steroids and/or immunosuppressant drugs.This study was approved by the Human Ethics Committee of Chiba University (protocol number 2083). PBMCs were collected from patients diagnosed with pulmonary sarcoidosis and from healthy controls between August 2020 and April 2021 at Chiba University Hospital. Patients with pulmonary sarcoidosis were diagnosed according to the recommendations of the ATS/ERS/WASOG statement , and allPeripheral blood was collected using a BD Vacutainer CPT Cell Preparation Tube with sodium citrate according to the manufacturer's protocol (#362760) . Briefly, the tubes containing blood were centrifuged at 1,500 rpm at room temperature for 20 min. After centrifugation, the plasma was removed from the uppermost layer. The PBMC layer was transferred to 15 ml conical tubes, washed with PBS twice, followed by the addition of Isogen , and then stored at −80°C.6 PBMCs, and each sample was transferred to 1.0 ml isogen reagent . The solution was vigorously vortexed and incubated at room temperature for 5 min. The solution was then centrifuged after adding chloroform, and the aqueous phase was carefully transferred to a new tube, following which 10 mg glycogen (Life Technologies) was added as a co-precipitant. RNA was precipitated by adding 600 μL of isopropyl alcohol. The RNA pellet was washed once with 75% ethanol and then dissolved in 10 μL RNase-free water. The concentration and quality of the RNA were verified using a Qubit fluorometer (Life Technologies) and an Agilent 2100 bioanalyzer, respectively. Purified total RNA (200 ng) was used for RNA library preparation, according to the instructions of the Quant Seq 3' mRNA-seq library preparation kit FWD for Illumina . The RNA libraries were sequenced on an Illumina NextSeq 500 system with 75-nt-long reads.Total RNA was extracted from 1.0 to 2.0 × 10http://bioinformatics.sdstate.edu/idep92/) and published paper .The present study included two groups: subjects comprising 8 patients with pulmonary sarcoidosis and 11 healthy controls. The subjects' demographics are shown in We prepared RNA-seq libraries from mRNA isolated from the PBMCs of subjects with pulmonary sarcoidosis and healthy controls. The RNA integrity number values of all samples were >8, and 26,472 genes from mRNA were obtained. After additional quality control methods, 18,139 genes were retained as DEGs for further analyses. Next, the count data obtained by RNA-seq were processed and analyzed using iDEP.92.2-fold change and FDR expression levels for the 18,139 genes expressed in these samples by volcano plotting with 270 DEGs (FDR < 0.05 and fold-change > 2 or < 0.5) highlighted in color. PCA enables us to project samples into two-dimensional space . We perfTo explore the pathways that are modulated in PBMCs of pulmonary sarcoidosis compared to that of healthy controls, we performed enrichment analysis  using GSEA . As shown in n = 4) with those of older age (n = 4)  to see if the findings described above become biologically irrelevant. PCA was performed by comparing gene expression patterns between older and younger patients with pulmonary sarcoidosis. The results showed that the two groups appeared to be undifferentiated, as shown in Significant difference in mean age between sarcoidosis and healthy controls was detected . Age is n = 5) with those of males (n = 3) to see if the findings described above become biologically irrelevant. PCA was performed by comparing gene expression patterns between the male and female patients with pulmonary sarcoidosis. The results showed that the two groups appeared to be divided, as shown in Sex difference is also a very important factor that could influence the transcriptional signatures. Therefore, additional transcriptome analysis was performed focusing on gender by comparing the data of females (n = 3) with those having only pulmonary lesion (n = 5) to clarify if differences in transcriptome of PBMCs exist between them. The results of PCA showed that the two groups appeared to be undifferentiated, as shown in Multiorgan involvements were observed in 3 out of 8 pulmonary sarcoidosis patients , therefoIn the present study, transcriptome analysis indicated that gene expression profiles differ in PBMC level between pulmonary sarcoidosis and healthy controls, probably reflecting the pathobiological state with granuloma formation. To our knowledge, the present study revealed, for the first time, the potential difference in gene expression profiles of PBMCs between healthy controls and pulmonary sarcoidosis without the influence of any immunomodulatory drugs such as steroids and/or immunosuppressant drugs. The present gene expression study using heterogeneous cell mixtures lacks insight into cell type-specific immune dysregulation. However, bulk RNA evaluation at the PBMC level could reflect some aspects of the clinical phenotype as a final product of cell-cell interactions among blood immune cells. Of note, changes in transcriptome of lots of mediators and pathways that were reported to be related to sarcoidosis, were detected in PBMC levels.The present study revealed that 270 genes were differentially expressed in PBMCs between subjects with pulmonary sarcoidosis and healthy controls. Enrichment analysis with GO analysis revealed that various biological pathways were enriched such as “Cellular response to IL-1,” “Cellular response to IFN-γ,” “Positive regulation of IL-6,” “IL-8 secretion,” “Mononuclear cell migration,” “Regulation of mononuclear cell migration,” and “Response to lipopolysaccharide (LPS),” all of which are reported to be in relation to granuloma formation in sarcoidosis lesion . In addiFirst, the terms “Cellular response to IL-1,” and “TNF signaling pathway” were listed in this study . In sarcNext, “IL-17 signaling pathway” was listed in this study . IL-17 hThe terms “Response to lipopolysaccharide” and “Toll-like signaling pathway” were listed in this study . LPS is + cytotoxic T cells  and were less likely to develop sarcoid-like granulomas within 5 years of cancer diagnosis   . The eth= 0.006) . Many as= 0.006) . TherefoIn the present study, additional transcriptome sub-analyses were performed to see apparent influence of differences in age, sex, and the lesions, although the sample number in each group was small –S3. The In conclusion, the current study suggests that bulk gene expression patterns in PBMCs are different between healthy controls and patients with pulmonary sarcoidosis. Most of the terms from enrichment analysis in the present study were different from those in a previous study that performed transcriptome analysis of PBMC comparing healthy controls with pulmonary sarcoidosis patients, more than half of whom received anti-inflammatory drugs. The changes in gene expression patterns of PBMCs could reflect the existence of sarcoidosis lesions and have an influence on granuloma formation in sarcoidosis. These new findings are important to strengthen our understanding of the etiology and pathobiology of sarcoidosis and indicate a potential therapeutic target for sarcoidosis.https://www.ncbi.nlm.nih.gov/, GSE192829.The datasets presented in this study can be found in online repositories. The names of the repository/repositories and accession number(s) can be found below: The studies involving human participants were reviewed and approved by Graduate School of Medicine, Chiba University. The patients/participants provided their written informed consent to participate in this study.TK and KT: conceptualization. KY, TK, DI, TI, and MA: data curation. KY, HS, TK, YH, and OO: formal analysis and methodology. KT: funding acquisition. KY, HS, TK, and KT: investigation. TK, KT, and TS: project administration. OO, KT, and TS: supervision. KY and HS: visualization. KY and TK: writing – original draft. TK, OO, KT, and TS: writing – review and editing. All authors contributed to the article and approved the submitted version.This research was funded by a research grant from the Intractable Respiratory Diseases and Pulmonary Hypertension Research Group, the Ministry of Health, Labour and Welfare, Japan (Grant Number 20FC1027).The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


Graphene-based composite aerogel (GCA) refers to a solid porous substance formed by graphene or its derivatives, graphene oxide (GO) and reduced graphene oxide (rGO), with inorganic materials and polymers. Because GCA has super-high adsorption, separation, electrical properties, and sensitivity, it has great potential for application in super-strong adsorption and separation materials, long-life fast-charging batteries, and flexible sensing materials. GCA has become a research hotspot, and many research papers and achievements have emerged in recent years. Therefore, the fabrication, structure, performance, and application prospects of GCA are summarized and discussed in this review. Meanwhile, the existing problems and development trends of GCA are also introduced so that more will know about it and be interested in researching it.  Aerogel, a highly porous material with low density and high specific surface area, is obtained by replacing the liquid in wet gel with gas without significantly changing the structure and volume of the gel network. Graphene-based composite aerogel (GCA) is composed of graphene and its derivatives graphene oxide (GO) and reduced GO (rGO) with other matrix materials. Its functions are mainly derived from graphene and its derivatives , while its structure and volume stability are mainly determined by other matrix materials . The resThe preparation principle of GCA includes three key processes: sol, gel, and drying. In the sol-gel process, the reactants are uniformly mixed and reacted in the liquid phase to form clusters of different structures. The sol of graphene-based materials and matrix may be obtained by chemical vapor deposition (CVD), hydrothermal reaction, chemical reduction, and vacuum carbonization . Then coGCA usually consists of graphene-based materials and inorganic 2D nanosheets materials, inorganic nanoparticle materials, synthetic polymers, and natural polymers. 3C2Tx (MXenes), transition metal sulfide (TMD), metal organic framework (MOF), hexagonal boron nitride (h-BN), layered double hydroxide (LDH), perovskite and black phosphorus (BP), and other hot materials . Sh. Sh31]. GCA has a porous network structure and low density. Pore structure is closely related to strength, thermal performance, and electrochemical performance. In addition, GCA can uniformly disperse the graphene nanolayers in the matrix in the form of a single layer or a few layers to reduce agglomeration. Different pore diameters of aerogels also affect their density, pore volume, and specific surface area. For example, pore volume is the volume of pores per unit mass of aerogel and is related to the inner and outer diameter. With the same inner diameter, the pore volume decreases along with the increase of the outer diameter, and with the same outer diameter, the larger the inner diameter, the larger the pore volume. Like specific surface area, pore volume is another important factor affecting the surface adsorption and loading properties of aerogels. The structural parameters, including specific surface area, density, and pore size of GCA, are listed in In terms of the morphology of aerogels, GCA can be roughly divided into two categories: porous structure and mesoporous core–shell structure. The common porous structures include honeycomb, microsphere, etc. The local compressibility and elasticity of aerogel honeycomb structure were well studied by density functional theory (DFT) . The hon2 drying. Liu et al. [Microspheres with mesoporous and core–shell structure produced by GCA exhibit greater strength and have wider application. These aerogels can usually be obtained using the sol-gel, blending, or other method to obtain hydrogels, which are then transformed into aerogel by freeze-drying or super-zero boundary COu et al.  preparedCompared with the mesoporous microspheres structure, the core–shell structure is more complicated. Researchers have adjusted the pore structure of GCA aerogels by controlling the freezing temperature and direction of ice crystals formed between graphene layers. In addition, in order to form dense nuclei and sparse filling shells, the freezing temperature gradient is needed to control the nucleation and growth of ice crystals to obtain GCA microspheres with core–shell structure . This unThe pore structure of GCA can be adjusted by controlling the concentration of polymers, inorganic nanomaterials, and graphene nanosheets. The template effects and self-assembly process of graphene-based materials can be used to change the pore structure of aerogels and other materials . In addi3O4, Fe3O4) is easy to recycle [Adsorption properties include physical and chemical adsorption. GCA aerogel’s abilities are connected with the structural design and performance of the material. In terms of structural design, 3D GCA usually has a larger specific surface area, higher porosity, and an interconnected porous structure, which can increase its combination with other functional materials and promote the diffusion of ions and molecules . In addi recycle . Introdu recycle . The adsorption of metal ions requires a large number of oxygen-containing functional groups  on the GO surface combined with positively charged heavy metal ions through electrostatic interactions, or surface complexes to form metal complexes . At the Furthermore, after the design and construction of roughness, the introduction of hydrophobic groups, and the thermal annealing reduction process, GCA was shown to have hydrophobic and lipophilic adsorption properties, which benefited oil–water separation . Using tThe key mechanical properties of GCA include compressive strength and deformation resistance. However, pure graphene aerogel is too weak for practical use. For this reason, various cross-linking agents or structural enhancers are introduced to prepare GCA with high elasticity and mechanical properties . For exaAs shown in −1·K−1, which makes it a suitable filler for the preparation of composites, with excellent thermal properties [The thermal conductivity of graphene is 5000 W·moperties . The inhoperties . Therefooperties  preparedIn short, the introduction of graphene-based materials improves the thermal performance of aerogel and provides a scheme to overcome the problem of energy consumption , which g7–108 S/cm, and makes it possible to prepare GCA with excellent electrical performance [The ultra-high electrical conductivity of graphene is one of its most attractive characteristics, which can reach 10formance . Howeverformance , which w2O3, Co(OH), Co3O4, MnO2, and MoS2 increase the electrical conductivity of GCA. For example, with the hydrothermal method, GCA was obtained by doping nano-Fe2O3 into graphene aerogel, and its specific capacitance was 81.3 F·g−1 at a constant current density of 1 A·g−1 and working potential of −0.8–0.8 V. GCA can also be functionalized by O, N, S, B, etc. [2O3 to produce GCA by form N-CQDs/rGO/Fe2O3 composite, and the preparation process is shown in 2O3 and stable high-conductivity N-CQD/rGO. The proper doping proportion can further improve electrical conductivity [Common metal oxides such as Fe B, etc. . Yun et  B, etc.  doped N uctivity . Yang etuctivity  successf2+. When the GO content in the aerogel was 5 wt%, the adsorption capacity of Pb2+ increased from 68.5 to 100 mg·g−1. The adsorption mechanism of common metal ions Pb2+ and Cu2+ may consist of intergroup coordination and complexation  of the aerogels  determinThe unique porous structure of GCA gives it good flexibility and elasticity, and it has become the preferred material for piezoelectric resistance sensors. In addition, GCA has great application potential in the field of energy storage and sensing, including supercapacitors, lithium batteries, solar cells, and fuel cells, because of its high conductivity, high electrochemical stability, and good mechanical stability . −1; when the stress increased from 0.05 N to 10 N, the response current varied from 0.44–2.89 mA to 10 N, so it could be applied in high-performance stress sensors , which was attributed to the highly conductive 3D multichannel, high charge transfer rate, and efficient transport guaranteed by the close interaction between dopamine and graphene [Furthermore, these materials could also be applied as biosensors to provide a wealth of information for early diagnosis of diseases and prevention of their evolution . Composigraphene . The mulgraphene . The ext2, SnO2, SnO2, TiO2) aerogel and heat-insulating flame-retardant materials, and graphene-based/synthetic polymer aerogel and graphene-/natural sugar-based polymer aerogel used as adsorbents to remove metal ions and dye contaminants in water. This paper reviews the material composition, preparation methods, structural characteristics, properties, and applications of GCA. Here we focus on several types of GCA, including graphene-based/2D nanomaterial (MXenes) aerogel for sensors and supercapacitors, graphene-based/inorganic nanomaterial  of GCA on its mechanical, thermal, and electrochemical properties. At the same time, the commonly used methods for preparing GCA are briefly described, including template method, self-assembly, chemical vapor deposition, 3D printing, and performance improvement strategies . GCA not only makes up for the deficiencies in the mechanical properties of graphene aerogel, but also retains excellent electrical conductivity, good mechanical flexibility, low thermal expansion coefficient, and other physical properties. It meets the special requirements for material properties in new fields, such as environmental purification, sensing, energy storage, biomedicine, heat insulation, and fire protection, and has become a hot spot in the field of graphene research in recent years. However, at present, the preparation method of graphene aerogel is relatively cumbersome, and it is necessary to find a quick preparation method to realize large-scale industrial production, although the chemical exfoliation method described in previous studies can be used to easily prepare graphene and its derivatives on a large scale. This still needs to be optimized to control the structure and size of materials. In terms of well-designed GCA, it is necessary to further explore the relationship between its properties and microstructure and optimize the preparation process parameters. For example, in the previous introduction, the pore structure of the aerogel was adjusted by controlling the formation of ice crystals between graphene sheets, but it is difficult to obtain uniform pore structure due to the existence of a temperature gradient, so it is still a difficult problem to skillfully control the morphology and size distribution of the product. In addition, most of the research has remained in the laboratory stage. Researchers should combine studies with production demand and broaden the scope of application.In summary, the future research direction of GCA will move toward the design and preparation of new graphene derivatives and their composite materials, with multi-dimensionality and better performance. Compared with GCA, it is difficult to use other materials in so many areas, especially energy storage, sensing, and adsorption, which are based on the characteristics of graphene-based and aerogel materials. With the continuous advancement of science and technology, GCA that is more environmentally friendly and has excellent application performance and better structural properties will be prepared in the future, which is both an opportunity and a challenge.