Cancer is one of the deadliest diseases worldwide, and there is a critical need for diagnostic platforms for applications in early cancer detection. The diagnosis of cancer can be made by identifying abnormal cell characteristics such as functional changes, a number of vital proteins in the body, abnormal genetic mutations and structural changes, and so on. Identifying biomarker candidates such as DNA, RNA, mRNA, aptamers, metabolomic biomolecules, enzymes, and proteins is one of the most important challenges. In order to eliminate such challenges, emerging biomarkers can be identified by designing a suitable biosensor. One of the most powerful technologies in development is biosensor technology based on nanostructures. Recently, graphene and its derivatives have been used for diverse diagnostic and therapeutic approaches. Graphene-based biosensors have exhibited significant performance with excellent sensitivity, selectivity, stability, and a wide detection range. In this review, the principle of technology, advances, and challenges in graphene-based biosensors such as field-effect transistors (FET), fluorescence sensors, SPR biosensors, and electrochemical biosensors to detect different cancer cells is systematically discussed. Additionally, we provide an outlook on the properties, applications, and challenges of graphene and its derivatives, such as Graphene Oxide (GO), Reduced Graphene Oxide (RGO), and Graphene Quantum Dots (GQDs), in early cancer detection by nanobiosensors. Cancer is the leading cause of mortality worldwide ,2. CanceBiosensor technology is a growing field to satisfy the need for sensitive and rapid detection problems . In addi2 hybridized, and the σ C-C bond is the strongest bond in materials, the pi (π) bond is responsible for the electron conduction of graphene [In electrochemical biosensors, a redox reaction takes place between the bioreceptor and the target molecule . The reagraphene . With thgraphene . Graphengraphene . GO is agraphene . GO is ographene . RGO hasgraphene . GQDs hagraphene . Much of2, sp3) [2 hybridization is a fine and zero bandgap semiconductor, but the sp3 hybridization diamond is a hard insulator. Graphene is highly thermally conductive, chemically stable, and flexible [2g−1) [The physical properties of carbon materials are related to their hybridization stats  ,39,40,41flexible . One of flexible . The chaflexible . Especiae [2g−1) ,33 and ie [2g−1) . It can e [2g−1) . The sene [2g−1) .2 carbon network and shows many defects, and functional groups make its insulators [3 carbons are converted to sp2 carbons. The electrical, thermal, and mechanical properties of RGO and graphene are similar [2 functional groups make RGO crafty for biological applications [Other unique properties of graphene, including its optical, magnetic, and high elasticity, make it a suitable monolayer structure for preparing several graphene-based nanocomposites. Graphene has one of the highest tensile strengths of all materials and a high Young’s modulus, which is the relation between stress and strain, that gives graphene its great mechanical properties ,48. Usinsulators . GO is nsulators . RGO is  similar . RGO exhications . RGO hasications ,58,59. Gications . GQDs exications . These Gications . GQDs haications .Usual sensing methods are expensive, require high-accuracy equipment and costly reagents, and the majority of reactions are not quantifiable in real-time. Graphene-based sensors are now being used as another method for the identification of cancer-related biomolecules. Graphene and its derivatives must be produced at a low cost to fabricate biosensors for early cancer detection successfully. The synthesis of graphene can be applied in two main ways: top-down (destruction) and bottom-up (construction) methods . Most ofThe top-down approaches such as arc discharge , oxidati2SO4. The solution was put in the ice bath and stirred for a few minutes on the stirrer. Then, 3 g of KMnO4 was added to the mentioned solution to turn the color of the solution green. After 5 min, 50 mL of distilled water was added dropwise to the obtained solution, and after 10 min, 100 mL of distilled water was added. Finally, 35 mL of H2O2 was appended to the solution and stirred for 24 h to synthesize GO well. As always, process safety and environmental cost need to be considered during process scale-up. Recently, the Hummer’s method has been used for the synthesis of GO because it is a fast and safe process [As shown in  process .4), acetylene (C2H2), ethylene (C2H4), and hexane (C6H14), to grow graphene sheets on metallic catalysts such as Cu and Ni [2, the deposition of GO is formed on the metal plate and at the end reduced to graphene. Graphene deposition scratches from metal plates are separated by HCL. In another method called epitaxial growth, utilizing carbon solubility in various substrates is a method used to produce graphene layers. The process begins by giving the substrate intense heat, and it allows the carbon to dissolve. This heat depends on the properties of the substrate. The carbon source can be added to the substrate using hydrocarbon molecules. The whole sample is then slowly cooled, reducing the solubility of carbon in growth, resulting in carbon atoms separating from the mass of matter and forming graphene islands on its surface. Different metals and compounds such as Ruthenium (Ru), nickel (Ni), and silicon carbide (SiC) can be used in this process [−1 of ethanol, 2 mg·min−1 was produced [The bottom-up approaches include chemical vapor deposition (CVD) , Substrau and Ni ,79. The u and Ni ,81. Methu and Ni ,83. Alte process ,85. Grap process . SiC was process ,88. In s process . In this process . From 16produced . Howeverproduced .Biosensors are diagnostic tools defined as having a biorecognition element for analyte specificity and a transducer for a measurable signal. There are various measurement methods for measuring biomarkers, and electrochemical measurement methods can be divided into the following categories:1. Amperometry, the most widely used technique for detecting cancer cells and cancer biomarkers, continuously measures the current resulting from the oxidation or reduction of an electrical species in a biochemical reaction.2. Chronoamperometry, in which a square wave potential is applied to the working electrode and a steady-state current is measured as a function of time. Potentiometers determine the difference in electrical potential between two electrodes when the cell current is zero. Potentiometric measurements are made through the Nernst equation, the relationship between concentration and potential. In fact, in this method, the measurement of potential is performed as a function of time in response to a constant current or a square wave.3. Voltammetry is an electro-analytical method that measures current through analytical potential change information. Due to the different methods of measuring potential change, there are also different voltammetric methods, such as cyclic voltammetry (CV), reciprocating voltammetry, linear sweep voltammetry (LSV), differential pulse voltammetry (DPV), square wave voltammetry (SWV), and adsorptive stripping voltammetry (AdSV). Among the various voltammetric methods, SWV and DPV are often used due to their high sensitivity .Many biorecognition elements have been used, ranging from naturally occurring to synthetic constructs . NaturalThe limit of detection (LOD) is commonly used as evidence of the quality of a biosensor. The limit of detection is expressed in units of concentration and, following the IUPAC definition, indicates the smallest solute concentration that a given analytical system is able to distinguish with reasonable reliability of a sample without an analyte. The biorecognition element describes both the selectivity and the sensitivity of diagnostic devices. Between the nanomaterials worked for biosensor fabrication, graphene and its derivatives have been displaying the most promise, since they present an enhanced signal response in a variety of sensing usages ,81. In aOver the last few decades, attempts have been made to utilize semiconductor field-effect transistors (FETs) in biological and chemical sensors due to their well-characterized behavior and ease of use of portable devices. In addition, the electrical measurement of bimolecular interactions is particularly desirable due to its adequacy for low-cost mobile sensors that could be used in the area by non-technical individuals . FET-basAn FET-based biosensor includes three electrodes—the source, the drain, and the gate—such that the section between the drain and the source functions as a biological detection component that interacts with the target analyte/biomolecules and senses their presence, concentration, and electrical activity. The biosensor then converts the biological information directly into a detectable signal . SubsequDue to the linear dispersion relation of the charge carriers in graphene, they have a very small effective mass and excellent carrier mobilities . FurtherAs a conductive channel substrate, many findings have been obtained through research on the contact resistance between graphene and metal to enhance the efficiency of the field-effect transistor. In addition, the need for high carrier mobility and luxurious functional groups has prompted a great deal of effort, such as the heating-assisted spray system for manufacturing mass production of RGO sheets and the interlayered quantum dots for elevating carrier mobility. Biocompatibility, ease of functionalization, and biocatalysis in the oxygen reduction reaction (ORR) are other outstanding features of graphene-based nanomaterials that are useful in the fabrication of GFETs for ultrasensitive and low-noise cancer detection ,119,120.v). Modified Cv FET with electrically activated antibodies showed good stability [It is important to maintain the stability of the antibody-modified surface during FET measurements. However, unlike other measurement methods, FET measurements use an electrical application on the gate area that can damage the surface. Electrical application may repel antibodies that are immobilized on the surface. Thus, preserving antibody-modified FET properties during measurements improves the reliability of FET antigen detection. Hidshima et al. evaluated three types of FET-modified antibodies to measure stability. The change in FET properties was determined three times in a row by calculating the change in the amount of threshold voltage change . In this study, anti-CEA was immobilized in a single-layer graphene channel using a PYR-NHS linker. The anti-CEA-modified GFET could achieve a limit of detection (LOD) of CEA less than 100 pg·mLproteins . In otheeins [−1 .In 2013, Kim et al. applied the R-GO FFET for label-free ultrasensitive diagnosis of a prostate cancer biomarker of α1-antichymotrypsin (PSA-ACT). When PSA-ACT complexes were placed on the R-GO channel substrate using monoclonal PSA, it caused a linear reaction of the gate voltage , caused by the protein–protein interactions on the R-GO FET sensor. They reported this detection of protein–protein interactions up to the femtomolar level with a dynamic range over six orders in the Vg, using minutes of the alteration as a sensitivity parameter. Finally, the R-GO FET biosensor successfully demonstrated high specificity in the diagnosis of SA-ACT of the femtomolar level .−9–1.0 U/mL) demonstrated a wide linear dynamic range with a low detection limit of 5.0 × 10−10 U/mL. During the process, the proposed FET currents are present in the presence of various interfering species commonly found in biological fluids, including CEA (1.0 × 10−3 U/mL), AFP (1.0 × 10−3 U/mL), and CA15-3 (1.0 × 10−3 U/mL). Comparison with CA125 (1.0 × 10−5 U/mL) was measured. According to the values measured in the bar graph of To increase the electrochemical reactivity of the FET biosensor system, Majd et al. designed an ultrasensitive aptasensor system based on multi-walled carbon nanotubes and RGO for label-free detection of ovarian cancer antigen 125 (CA125). The sensor has a simple design based on the noncovalent bonding of MWCNTs/conjugated aptamers on multilayer Graphene Oxide nanosheets and its integration with polymethyl methacrylate (PMMA) as a suitable substrate for designing flexible field-effect transistors. The presence of MWCNTs caused the immobilization of molecules due to the high surface-to-volume ratio. The designed aptasensor for CA125  of the dielectric medium. Interaction between the immobilized receptors on the metal surface and the analyte molecules causes a variation in the sensed medium’s refractive index (dielectric), which leads to an alteration in the propagation constant of the surface plasmons. This phenomenon affects the resonance condition of surface plasmons with specific surface plasmon waves (SPW) that have interactions with the incident p-polarized light of the same propagation constant. The energy of light photon transfers to the surface plasmons at the resonance angle, and the reflectance of the light significantly decreasing, results in forming a sharp dip in the SPR curve (reflectance with respect to the incident angle) ,134. ThePhase detection based on coherence is usually very sensitive to mechanical movements in optical components and ambient noise, which leads to phase measurement errors. The stability of the SPR biosensor in the time axis is also required to monitor the biological response over time.−7 RIU/RU was reported during the 80 min measurement, which is similar to several high-sensitivity-phase SPR systems [Wang et al. evaluated an efficient SPR phase biosensor for targeted drug delivery screening. The sensitivity of the sensor was determined by the SPR signal of a set of concentrations of sodium chloride solution, and its stability was estimated by oscillating the SPR signal of the system during the 80 min measurement process with a sample containing 0.9% sodium chloride. A significant reduction in ideal stability noise of 6 × 10 systems .Graphene-based nanomaterials have a very high surface-to-volume ratio, which enhances the biosensor sensitivity due to the efficient light absorbing on the sensing layer by p–p stacking interaction between biomolecules’ carbon-based ring structure hexagonal units of graphene sheets . Other s2 layered surface plasmon resonance (SPR) biosensor with a graphene-coated SPR biosensor. The numerical values obtained showed that the SPR biosensor coated with graphene-MoS2 compared to a single layer of graphene SPR biosensor is 175% more sensitive [−1 with the LOD of 15 ng·mL−1, which was 15.3 times lower than the conventional SPR biosensor for detection of the same biomarker [Biplob Hossain et al. conferred numerical modeling of a graphene-coated fiber-optic surface plasmon resonance (SPR) biosensor for detection of genetic biomarkers involved in early breast cancer by means of DNA hybridization. The technique used in this sensor is based on the attenuated total reflection (ATR) method to detect the hybridization of deoxyribonucleic acid (DNA) with individual point mutations in the BRCA1 and BRCA2 genes. To detect breast cancer biomarkers (916delTT and 6174delT), SPR and SRF angles can be used, which are insignificant for uncoordinated DNA strands, while being a significant complement to DNA strands. As shown in ensitive . In otheiomarker .Biomolecular imaging and biomarker detection can be performed using fluorescent nanomaterials and labels, a highly sensitive and selective method with adequate spatiotemporal resolution and low cost for application . NumerouFor removing the technical obstacles of conventional organic labels, many fluorescence-emitting nanomaterials such as dye-doped silica nanoparticles (DDSNs), fluorescent gold/silver metal nanoclusters, lanthanide-doped nanomaterials, upconversion nanoparticles (UCNPs), carbon nanomaterials, and fluorescent semiconductor quantum dots (QDs) have been utilized in the fabrication of fluorescent biosensors ,156. GraEven though the complete fluorescence mechanism of carbon nanomaterials is not understood, various types of them such as carbon nanotubes, GO, RGO, GQD, CQD, etc., have been used in fluorescent biosensors ,160,161.In 2015, Zhang et al. showed that with a nanofiber membrane with electrospinning of Graphene Quantum Dots for dual-purpose fluorescent and electrochemical biosensors, the fluorescent intensity is almost uniform, which determines the excellent stability of PVA/GQD nanofiber membranes .Xu et al. designed a fluorescent aptasensor to detect four biomarkers of AFP, HER2, CEA, and VEGF165 simultaneously in the living cell. GO sheets were modified by four fluorophore-labeled aptamers, including FAM, Cy5, and AF405, and after the formation of the aptamer–protein complex, these fluorophores detached from the GO sheet and biomarkers were detectable by four different colors. This procedure proved to be rapid, biocompatible, and highly specific for the diagnosis of related cancers . In otheIn 2021, MA et al. reported that they used DNA nanomaterial attached to the GO surface to detect liver tumors. To analyze the selectivity of target and non-target cells, these cells were stained with and without GO by nanomaterial DNA. In the absence of GO, the comparison between target and non-target cells was insufficient. However, in the presence of GO, diffusion in non-target cells was very weak compared to target cells, indicating the role of GO in the detection of target cells. In in vivo studies, the liver tumor was stained well with the GO-based DNA nanomaterial. The studied system showed that it is highly able to target liver cancer cells. It also works well in the detection of fluorescence imaging of liver tumors and chemotherapy .Electrochemical sensing essentially needs a reference electrode, a counter (auxiliary electrode), and a working electrode, sometimes termed as the sensing or redox electrode. The ref2 and H2 density on the edge-plane defect spots, they bring about a great deal of electron transfer for biospecies [A wide range of molecular identification elements can be used by electrochemical biosensors to detect biomarkers. A number of advantageous electrochemical strategies for detecting cancer biomarkers include techniques such as voltammetry (CV) . The useospecies .Modification of electrodes with graphene-based nanomaterials also causes electrochemical species to distribute on the surface uniformly, and their 2D structure provides a high surface-to-volume ratio, which results in a suitable substrate for detecting adsorbed analytes. The electron transfer rate directly correlated with the exponential distance between the electrode surface and electrochemically active center of the bioreceptor, and graphene-based modification can dramatically reduce this distance to facilitate the electron exchange. This phenomena takes place on the edge of graphene sheets and/or at defects in the basal plane by nanowiring between active electrochemical sites and electrode surfaces to transfer electrons directly that promote sensing applications ,184.−1 [Akbari et al. designed an electrochemical biosensor for prostate cancer biomarker detection using GO/Au nanostructures, and this article showed that the GO/AuNP composite improves the electrical conductivity and biocompatibility . Heydari−1 . A DNA b−1 .−14 to 10−8 M with a correlation coefficient of 0.972 and a detection limit of 3 fM. The results show that the electrochemical biosensors of the graphene-modified glass electrode can be used as an alternative to conventional methods for detecting the early stages of cancer [In 2020, Asadi et al. developed a graphene-modified glassy carbon electrode electrochemical biosensor to detect miRNA-21, a biomarker in early prostate cancer. A molecular linkage agent was used to immobilize DNA on the surface of a graphene-modified glass carbon electrode. Charge transfer resistance (Rct) was measured by electrochemical impedance spectroscopy before and after hybridization. The electrochemical biosensor demonstrated a linear impedimetric response between ΔRct and logarithm of miRNA-21 concentration ranging from 10f cancer .−1 and in the range of +0.8 to −0.4 V. The redox peak currents shown in In 2021, Jozghorbani et al. investigated the diagnosis of carcinoembryonic antigen (CEA) using a label-free electrochemical immunosensor to tether the antibody to the electrode surface. In this study, CV and EIS techniques were used. They first coated the GC electrode surface with RGO. The CV measurements were performed in a 0.1 M solution of PBS (pH = 7.4) containing a 5 mM ferro-ferricyanide probe against the Ag/AgCl reference electrode at a scan speed of 25 mV sIn Raman scattering, photons inelastically lose (Stokes) or gain (anti-Stokes) energy because of molecular vibrational events and represent information about the molecular structure enabling in situ and real-time detection . SurfaceIn bioanalysis, SERS-based biosensors have the following advantages: (1) ability to represent biomolecules’ intrinsic fingerprint molecular information and ultra-high sensitivity down to the single-molecule level; (2) narrow peak bandwidth relative to fluorescence spectroscopy with strong tolerance to photobleaching and photodegradation; (3) many ways to appeal to specific applications for signal enhancement substrates of varying sizes and shapes; (4) a greater depth of laser penetration enables both diagnosis and imaging in vitro and in vivo . One key downside of traditional silver-based SERS substrates is their low physical stability due to oxidation, which has a strong effect on their sensitivity and quality of efficiency. SERS-active metallic nanostructures are typically protected by a stable protective coating or shield constructed from inert materials, such as metal oxides and carbon materials, to overcome this restriction ,196. AmoPractical applications of SERS nanotags require SERS signal stability when nanotags are exposed to the constant light of relatively high-power laser light. These SERS-related problems limit the quantitative analysis of reading signals in sensor applications and prevent the development of a reliable, quantitative SERS-based detection platform. Therefore, the protection and stabilization of SERS nanotags are key factors in the development of reliable diagnostic assays. Smolski et al. showed that following the formation of an encapsulating layer on Raman molecules at the surface of gold nanoparticles improves signal stability in the long-term exposure to intense laser light. Modified molecules have higher SERS intensities and therefore show their stability over time .In addition, several intriguing properties, such as high optical transparency, high carrier mobility, chemical inertness, and biological compatibility, are often combined with graphene and its derivatives . A varie−1 wave number as well as spectral narrowing. The chemical interaction between RGO and tumor cells can be seen from the distortion at the characteristic peaks of graphene. In connection with the chemical mechanism of RGO, the Ag-RGO-Au system has also been used to identify tumor cells without the use of biomarkers. The results showed that free-labeled tumor cells and normal cells, due to interaction with RGO located on the Ag-RGO-Au substrate, could be characterized by Raman changes at specific peaks). The results are shown in Yi et al. developed an SERS-based biosensor to detect tumor cells. In this system, RGO was sandwiched between Ag and Au nanostructures. The Ag-RGO-Au system has a strong chemical mechanism due to the charge transfer between RGO and the target molecules. The SERS sensor based on Ag-RGO-Au was tested for sensitive detection of tumor cells in the presence of human tumor cells, liver cancer cells (BEL-7402), and normal human liver cells (202 liver cells). Tumor cells do not show a characteristic signal in the range of 1000–3200 cm-1 in the Raman spectrum on the Si slide. Placing labeled tumor cells on the Ag-RGO-Au substrate causes significant differences in the Raman spectrum that may indicate tumor cells. In addition to the changes in the width and shape of peaks D and G compared to the peaks for Ag-RGO-Au, the intensity of the peaks also increases. Especially for peak D, there is a clear shift in the 25 cmIn 2018, Liang et al. used a label-free graphene/gold nanopyramid-based SERS biosensor to detect colon cancer p53 −/− cells from p53 +/+ colon cancer cells. The hybrid SERS biosensor is capable of detecting p53 −/− cells from the p53 +/+ cells of three different cell states, live, dead, and burst, with an average 81% sensitivity and 97% specificity. These results show the potential of this SERS graphene hybrid for cancer detection .Electroluminescence or electrogenerated chemiluminescence (ECL) is the shared area of electrochemistry and chemiluminescence (CL). In this mechanism, by applying a potential on the electrode’s surface, the electrochemical energy is being converted to radiative energy ,205,206.Due to the convergence of electrochemical and spectroscopic approaches, ECL has many benefits over chemiluminescence and photoluminescence, such as improved temporal and spatial modulation of light emission, high sensitivity due to lack of light excitation and a wide dynamic range, and fast detection in a low volume of sample. Furthermore, ECL has been successfully used for diagnostic purposes in real samples and complex matrices such as blood, urine, and cell lysates because of its remarkable signal-to-noise ratio (S/N) .Nanoparticles possess outstanding electrochemical, photonic, and magnetic properties that make it possible for ECL sensing designs to be superior transducers ,211. Due2O82− system, which could promote both C•− and SO4•− production in the ECL system to produce more C*+, resulting in an almost 48-fold amplification of the ECL [Although the exact PL process of CQDs and GQDs is still argumentative, π-plasmon and surface or edge defects are related to the broad optical absorption and photoluminescence emissions of carbon-based QDs. The few PL colors and poor quantum yield are still the main shortcomings of CQDs and GQDs in sensing applications. In addition, surface passivation may also impact CQDs’ ECL behaviors. The oxidized CQDs have outstanding ECL behaviors without any surface passivation from a top-down technique. However, the CQDs passivated via a bottom-up route with some capping reagents, displaying erratic ECL signals with elevated background interference . CDs wer the ECL .After reviewing the types of graphene-based biosensors, Recent advances in the development of biosensors were discussed in this study. Recent research on biomarkers over the past decade has shown that biosensors can detect cancer in the early stages with minimal amounts of biological material and various diagnostic methods. Despite the invention of various biosensors, all of these sensors still have advantages and disadvantages. Powerful portable and user-friendly biosensors still have challenges as long as they become a reliable diagnostic method for cancer diagnosis. Challenges and future prospects in this field are rapidly being explored and developed. The issue is, what has led to the rapid progress in this area? Most research refers to nanomaterials or nanoscale measurements, or in many cases both, as the cause of rapid progress. Research and developments of current nanobiosensors are focused on reducing the mentioned problems such as high sensitivity and selectivity, accuracy and precision, and cost reduction. Hence, various methods have been used to minimize the challenges in biosensors. The most important solution proposed is the integration of different mechanical, electrical, chemical, and biological systems using special nanomaterials. If this sequential process occurs, the new diagnostic nanobiosensors could be extended to highly sensitive cells for cancer diagnosis and treatment without serious side effects .Limit of detection (LOD) is a critical performance characteristic that requires careful evaluation during method validation. LOD is generally expressed as the amount of analyte that the analytical method detects in at least 95% of cases. Cancer dosage markers may be very low, so the use of high-LOD methods puts the researcher at risk of negative diagnosis. Very low LODs allow the detection of target biomarkers without enzymatic amplification. Therefore, the development of new techniques with selectivity, sensitivity, and low limit of detection (LOD) is very important in routine diagnosis . For thiIn this regard, Hussein et al. reported in 2019 that the limit of detection (LOD) of the biosensor was about 2 ng/mL, which is 50 or 60 times lower than the detection of antigen by ELISA treated with gold nanoparticles (LOD = 100 ng/mL) and conventional ELISA .Circulation of tumor cells (CTCs), found in the peripheral blood of cancer patients, can be used to detect cancer early. With CTCs, 1 cell per 10 mL can be important, while for pathogens, it can be one microbial species per liter in water quality analysis. Larger volumes pose more challenges for biosensors because these low concentrations require multiples of the sample to be analyzed. Such large volumes can be challenging even for microfluidics, although the separation of CTC by Warkiani et al. solves the higher volume challenge . In this regard, Pudineh et al. examined the heterogeneous phenotypes of circulating tumor cells (CTCs) in whole blood to discover the complex and dynamic features of these potentially vital clinical markers. This task is challenging because these cells are present at parts per billion levels among normal blood cells. To characterize CTCs, they developed a new method based on nanoparticle activation called cytometry. Accordingly, it indexes CTCs based on their superficial expression phenotype. They used a microfluidic chip to process whole blood samples . It is tIn addition, to solve the mass transfer problem using dispersed electrodes for PSA detection, Wu et al. compared the performance of finite dispersible electrodes with a similar sensor prepared in the same way on a normal flat electrode. The dispersible electrodes were used to solve the problem of mass transportation with very low detection sensors. This features the detection limit from the flat sensor to the dispersible electrodes reduced from 7.05 pM to 3.0 fM. Similarly, detection limits of up to 15fM or even lower have been reported for a signal increase .Stability of nanobiosensors in electrodes.High sensitivity of biosensors to changes in environmental and medical conditions.Ability to reuse nanobiosensors.Problems caused by biocompatibility or non-toxicity to the environment.Complex technology for making electrochemical nanobiosensors.The complexity of the interaction method of nanomaterials and biomolecules.Processing, creating special features, and connection problems.Access to high-quality nanomaterials and the nature of these nanoscale compounds on the electrode plate .Ideally, for graphene-based biosensors, we need sensors with high response to the target analyte or molecule that have little or no response interference species. To achieve this goal, more working probes must be used to improve the detection of the target analyte or molecule . DespiteReproducibility, controllability, and scalability are other challenges that need to be overcome. Detecting cancer biomarkers in real samples such as blood plasma, etc., is also a challenge. Because real samples have different proteins, ions, and chemical species, they can be misdiagnosed. One possible way to solve this problem is to disable the sensor surface with an antifouling agent to focus on the target . Thus, aToday, biosensors are used as a sensitive and rapid diagnostic tool in the early detection of cancers. In addition to making early diagnosis and treatment options more accessible to patients and improving their quality of life, biosensors can develop multiple sensors, differential and semi-selective, that can measure multiple markers in a single unit. The biosensors are able to read direct responses as positive and negative responses of biological fluid, including biomarkers, and also lack limitations such as throughput limitations and small sample volumes. Because circulating cancer biomarkers are generally found in small amounts in the background of non-target cells, EVs, and biomolecules, the combination of magnetic nanomaterials and electrochemical biosensors is appropriate to overcome this diagnostic challenge. The use of nanomaterials in the manufacture of biosensors for the detection of biomarkers is significant because these cases increase the range of detection and increase the sensitivity of the biosensor. Graphene and its derivatives  are used in the fabrication of biosensors because of their high surface area, optical properties, and high thermal and electrical conductivity. In this study, the methods of synthesis of graphene and its derivatives were investigated. Oxidative exfoliation-reduction, CVD, and LPE have a high potential for industrial implementation. Finally, in order to synthesize graphene, the environmental hazards, cost, and quality of synthesized graphene should be considered. The use of graphene-based materials for biosensing has achieved great success in a short time. Recent studies in this literature review indicate that, among various detection methods, electrochemical graphene-based cancer biosensors are the best option, due to their high sensitivity in a rapid assay. Graphene-based biosensors show high sensitivity and can be employed for the detection of cancer, and graphene is a super new material for biosensing. The future development direction of graphene-based biosensors should be more portable, reproducible, miniaturized, and high-throughput in detection, and the future development of these 2D graphene nanomaterials will be further developed and tailored for the specificity of receptors.


Twisted van der Waals heterostructures were recently found to possess unique physical properties, such as superconductivity in magic angle bilayer graphene. Owing to the nonhomogeneous stacking, the energy of twisted van der Waals heterostructures are often higher than their AA or AB stacking counterpart, therefore, fabricating such structures remains a great challenge in experiments. On the other hand, one dimensional (1D) coaxial van der Waals structures has less freedom to undergo phase transition, thus offer opportunity for fabricating the 1D cousin of twisted bilayer graphene. In this work, we show by molecular dynamic simulations that graphene nanoribbons can self-assemble onto the surface of carbon nanotubes driven by van der Waals interactions. By modifying the size of the carbon nanotubes or graphene nanoribbons, the resultant configurations can be controlled. Of particular interest is the formation of twisted double walled carbon nanotubes whose chiral angle difference can be tuned, including the 1.1° magic angle. Upon the longitudinal unzipping of such structures, twisted bilayer graphene nanoribbons can be obtained. As the longitudinal unzipping of carbon nanotubes is a mature technique, we expect the strategy proposed in this study to stimulate experimental efforts and promote the fast growing research in twistronics. Carbon nanotubes (CNTs) and graphene are among the most exciting low dimensional materials that possess extraordinary properties, such as ultrahigh strength, unique configuration dependent electronical conductivity and magnetic properties, etc. Such unusual properties make CNTs and graphene promising for applications in a wide range of areas ,6,7,8,9.Recent progress shows that by stacking one layer of graphene on top of another, the formed bilayer graphene exhibits more distinct properties than its monolayer counterpart, e.g., the open up of an electronic band gap . SimilarOn the other hand, although twisted bilayer vdW heterostructures have shown great promise in electronic devices, their mechanical and thermal stability remains a pressing issue ,23,24. TInterestingly, as graphene’s 1D counterpart, CNTs are generally regarded as rolled up of graphene layers and multi-walled CNTs (MWCNTs), and can be composed of co-axial single-walled CNTs (SWCNT) of different chiralities. The different combination of chiralities among inner and outer CNTs can also result in rich electronic states. Furthermore, several groups have shown that MWCNTs can be unzipped or partially unzipped to 1D graphene nanoribbons (GNRs) or GNR-CNT junctions ,34,35,36Motivated by this scenario, in this work we propose a strategy to fabricate 1D vdW heterostructure via self-assembly of GNR onto the surface of SWCNT. The size of the GNR and SWCNT can be used to tune the resultant heterostructure with the desired orientation, i.e., with a particular twist angle between the inner and outer layer. Upon partially unzipping the 1D vdW heterostructure, the resultant GNR bilayer is shown to exhibit a twisted moire pattern. This strategy is expected to provide new alternatives to synthesizing magic angle bilayer graphene, or other twisted phases of 2D materials.The molecular dynamics (MD) simulations are performed using the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) . The gen2 is placed next to the SWCNT. After a few picoseconds (ps), the potential energy of the system displays a notable decreasing trend  SWCNT template as an example, three phases are observed, when the length of the GNR is as large as 70 nm, a longitudinal (L) wrapping is observed, forming multi-layered nanoscrolls. When the length is small, in-between 5 nm and 10 nm for example, helical (H) wrapping is achieved. Meanwhile, for an intermediate sized GNR, the edges of the helical structure attract to each other, and then make contact to form a tubular (T) structure. A widthwise (W) wrapping is also observed for the  SWCNT template, which has a similar size as the  SWCNT, the reason can be attributed to the fact that commensurate stacking between SWCNT and GNR can reduce the total potential energy of the system. Therefore, for chiral SWCNTs, H phases are preferred for small GNR, while for zigzag or armchair SWCNT templates, W phases are preferred. The observed phases are summarized in 2 nanotubes on SWCNT template; this process shares some similarities with ours, but the temperature is much higher in the experiment. More progress has also been recently made towards producing various 1D structures, such as the scrolls or ribbons in CNTs [One interesting feature observed in the T phase is that the size of the GNR does not have to be exactly 2πR, here R = r + 0.34 and r is the radius of the SWCNT, as depicted in  in CNTs ,45,46. S in CNTs ,48,49, bθ is the twist angle of the GNR after wrapping. We have run simulations with GNRs of different length to wrap a template SWCNT, the resultant twist angle is plotted as a function of L in For the chirality of the inner wall, the synthesis of SWCNT with the desired chirality has shown enormous progress, while for the orientation of the outer wall, according to the model presented in θ in Equation (1) equal to 1.1° are used to wrap the SWCNTs. The resultant twisting angles are found to agree well with predictions. Shown in This relationship means that the chirality of the outer wall can be controlled by the size of the GNR. For example, to obtain the magic angle between the inner and outer wall of the DWCNT, one can take a zigzag SWCNT as the template, then, according to the size of the SWCNT and the relationship in Equation (1), a particular sized GNR can be chosen to wrap around the SWCNT to form a 1.1° twist angle. We demonstrate this scenario in our simulations, as a representative example shown in We next proceed to study the stability of the as-formed structures under various temperature conditions, as representative results shown in As mentioned above, several groups have experimentally demonstrated the fabrications of layered GNRs via the unzipping of MWCNTs; a recent work by Chen et al.  showed t2. Future work towards fabricating multilayered vdW structures with precise twist should also be of high interest to this field, as recent experimental work has shown that such structures are also host interesting [In conclusion, we show by molecular dynamic simulations that graphene nanoribbons can be self-assembled to the surface of SWCNTs to form various heterostructures. If the size of the SWCNT and the GNR is well designed, the DWCNTs of particular twisting can be obtained; this offers a plausible platform for unzipping towards twisted bilayer graphene, including magic angle bilayer graphene. Upon unzipping, the twist angle for the resultant bilayer graphene remains almost unchanged. The obtained 1D vdW heterostructures is demonstrated to exhibit good structural stability under temperatures from 5 K to 300 K. This strategy can also be used to fabricate 1D vdW heterostructures composed of other elements, such as BN and MoSeresting . We expe


Foundation Doctors are exposed to a range of specialties within the Foundation Programme, with 20.9% completing a psychiatry rotation. Those who do not have a psychiatry rotation may have little experience other than what was acquired in undergraduate training, despite being expected to care for patients with mental health problems. According to Mind (2017), one in four people will experience a mental health problem each year thus essential that our medical workforce know and understand the basic principles of psychiatry to aid their management of core psychiatric conditions. The aim of this project was to improve mental health literacy among Foundation Doctors by improving their communication, formulation and risk management skills. Another objective was to encourage uptake to Psychiatry and help plug the high number of unfilled Consultant posts.The initial pilot was carried out between January and June 2021 over zoom and the sessions were optional. A survey was completed to find out which topics were most relevant and common themes included MCA/MHA interface, risk management and treatment of various conditions. These themes were incorporated into 90-minute sessions which included interactive case-based discussion in small breakout groups and some didactic teaching. The six session topics were EUPD, Dementia, Depression, Delirium, Substance Misuse and Alcohol Misuse. The sessions were facilitated by clinicians of mixed experience from Foundation Doctors to Consultants. Participant knowledge was tested using pre- and post-session quizzes and a working group reviewed feedback, making relevant changes subsequently.Feedback was majorly positive, and attendees valued the interactivity, breakout rooms, case studies and choice of topics. Suggested areas of improvement were having more time for discussion, technical difficulties, and less psychiatric ‘jargon’, but these tended to be isolated comments. Five out of six sessions showed an improvement in assessment scores afterwards, with an average improvement of 12.6% (average pre-session score of 70% and average post-session score of 82.6%). One session showed a decrease in the post-session quiz scores which on reflection showed that the questions in the assessment covered material not included in the session.The virtual programme was an effective way of improving knowledge and confidence in psychiatry. Whilst the sessions were positively received and showed improvements in post-session scores, there were some limitations which will be addressed and used to develop future training. There is now more mental health woven throughout the new Foundation curriculum and expected that much of this content will be covered during Foundation Training.


Pristine graphene (GR) sheets were potentiostatic treated with sulfuric acid and were oxidized at 1.4–2.0 V constant potentials to obtain numerous nanobuds and peeled nanoballs. Scanning electron microscopy was used to determine the morphology of electrochemically treated GR nanosheets. Fourier transform infrared, X-ray diffraction analysis, and Raman spectroscopy were used to characterize the structure of samples. The above results indicate that amounts of nanobuds were in situ grown on the surface of GR sheets at a constant potential of 1.4 V was added to the GR electrode. With the constant potential increasing, the nanobuds grew into the nanoballs, exfoliating from the surface of graphene sheets, whereas the peroxidation of graphene sheets occurred at a higher potential of 2.0 V, leading to the formation of a large amount of graphene oxide fragments. Therefore, the optimal processing parameter of the formation of carbon nanoballs was under the constant potential of 1.8 V for 500 s.Novel carbon nanostructures, carbon nanobuds and nanoballs  in situ grown on graphene, have been synthesized by the electrochemical method in this study.Novel carbon nanostructures, carbon nanobuds and nanoballs  Diamond and graphite have been studied by humans as the earliest isomers of carbon. Since the discovery of fullerenes by Kroto et al. in 1985, new structures of fullerenes have been continuously predicted or discovered beyond the individual clusters themselves.1–3 The emergence of fullerenes opened the door to a new set of nanoscale carbon isomers, and fullerenes are considered to be the third isomer of carbon after the discovery of diamond and graphite.4,5 They consist of nearly 60 carbon atoms, denoted by C60. In 1991, Iijima discovered carbon nanotubes which played an important role in the field of polymer composites.6,7 In recent years, as the research on carbon nanotubes and nanomaterials has intensified, their promising applications have continued to show.8 In 2004, two scientists from the University of Manchester, UK, Geim and Novoselov, discovered that they could obtain increasingly thin graphite sheets in a very simple way. Finally, they obtained a sheet consisting of only one layer of carbon atoms, which is graphene.9–11 Graphene is a new material in which carbon atoms connected by sp2 hybridization are tightly packed into a single layer of two-dimensional honeycomb lattice structure. With excellent optical, electrical, and mechanical properties, graphene holds significant promise for applications in materials science, micro and nano processing, energy, biomedicine, and drug delivery and is considered a revolutionary material of the future.12,13 However, for each of these materials there are their drawbacks and challenges. For example, when functionalizing carbon nanotubes or fullerenes, it usually destroys its kind of perfect structure and thus its excellent properties. With the development of carbon isomers and the endless attempts of scientists to combine two or more different carbon nanostructures with each other, a number of new carbon nanohybrids have been created. Among them, carbon nanobuds are the brightest product. They are generated by attaching a fullerene to a carbon nanotube. Both experiments and theories show that carbon nanobuds are more easily functionalized. Theoretical simulations also show that the electrical conductivity of the nanobud depends on the details of its geometry.14 Despite their relative novelty in the scientific community, carbon nanobuds have shown their potential as a useful nanomaterial. Field emission measurements suggest that they may be advantageous compared to carbon nanotubes or fullerenes alone. With that said, fullerenes, carbon nanotubes and graphene, the three most famous sp2 nanocarbons, have generated a great deal of interest in the scientific and technological community. Given the extensive research on these amazing nanocarbons, these nanocarbons show great promise in a wide variety of applications ranging from high-performance composites to electronic and energy storage devices to biomaterials.15–18 Researchers have never stopped moving forward on the road to a new era of nanocarbon. Carbon nanobuds (CNB), a novel carbon nanostructure, have been synthesized recently via covalently bonding C60 buckyballs to the sidewall of a single-walled carbon nanotube (SWCNT) through cycloaddition reaction by Nasibulin19et al.Carbon is one of the earliest elements that humans have come into contact with and one of the earliest elements that humans have utilized. There are many isomers of carbon in nature, such as diamond, graphite, fullerenes, carbon nanotubes, graphene, 2 hybridized carbon bond is a basic building block of CNT, fullerenes, and graphite. Hence, we consider that there would be a structural transformation from graphene to other allotropes of carbon. Some mechanism or theory with respect to this translation of the different allotropes of carbon has been approved. Uberuaga20et al. studied the fullerene and graphene formation from carbon nanotube fragments by longtime annealing using the accelerated molecular dynamics methods. These results suggest that fragments from nanotubes exhibit surprising behavior, unfolding to form thermodynamically unfavorable graphene fragments. Manna21 has reported computational studies on non-covalent interactions of carbon and boron fullerenes with graphene. Chuvilin22 has reported the direct transformation of graphene to fullerene; scanning electron microscopy directly visualized a process of fullerene formation from a graphene sheet. Georglk et al.23 successfully prepared carbon nanobuds using pristine graphene nanosheets (pG) and C60 as reactants. The prepared graphene nanobuds exhibited significantly improved dispersion and abundant aromatic properties, which also provided higher electrical conductivity.As mentioned above, fullerenes, carbon nanotubes, graphene and graphite have a similar structure and electronic properties, and graphene composed of an spAlthough graphene and fullerenes are interconvertible in principle, a simply viable route to translation from a flat graphene sheet to these carbon cages remains a mystery. In this article, direct evidence for the formation of a novel carbon hollow sphere from graphene nanosheets by the electrochemical method will be reported. Carbon nanobuds and fullerenes can be efficiently generated from graphene under the potentiostatic electric field, and this process can be observed with a scanning electron microscope.2.2.1−1) were used for GR deposition. Analytical grade reagents, H2SO4 (98 wt%) and ethanol  were used without any pretreatment. All solutions were prepared from de-ionized water.Graphene nanosheets (C > 99.5 wt%) were bought from Nanjing Xianfeng Nanomaterials Technology Co., Ltd. ITO-PET conducting films  as the reference electrode. The potentiostatic treatment was carried out from 1.4 V to 2.0 V for 500 s using a computer-controlled electrochemical analyzer . Finally, these resultant GR-PET electrodes were cleaned with deionized water several times and dried at 60 °C in a vacuum for 24 h . The phase composition was identified by X-ray diffraction  at a scanning speed of 10° min−1 and a scanning range of 5°∼70°.The micromorphologies of GR electrodes were observed by field-emission scanning electron microscopy  equipped with energy disperse spectroscopy . Fourier transform infrared (FTIR) spectra were recorded in the range of 500–4000 cm3.3.1The morphologies of GR films potentiostatic treated at different potentials are shown in A large number of nanobuds and several nanoballs grown on the local area of GR sheets at 1.4 V are shown in 60. In this article, scanning electron microscopy directly visualizes, in real-time, a process of carbon nanoball formation from a graphene sheet.Quantum chemical modeling explains four critical steps in a top-down mechanism of nanosphere formation: (i) loss of carbon atoms at the edge of graphene under the electric field, leading to (ii) the formation of pentagons, which (iii) causes the curving of graphene into a bowl-shaped structure, like graphene ‘buds’ and which (iv) subsequently zips up its open edges to form a closed sphere structure. This is the most widely accepted mechanism of the two-dimensional graphene layer structure dissociating into very small clusters of carbon nanoballs such as CAs the constant potential increased to 2.0 V, instead of nanospheres, irregular bulks were formed under higher potential as shown in Therefore, the shape and size of the carbon clusters embedded in graphene nanosheets can be tailored by optimizing the constant potential. In conclusion, the formation of carbon nanoballs shows that the best constant potential was 1.8 V for 500 s, confirming that nanoballs were very stable at room temperature.3.2−2. That is, the GR film may be oxidated and doped with SO42− ions on the ITO-PET film from 1.4 V to 2.0 V. Moreover, the current density gradually increases along with the rise of constant potential; that is, the growth rate of carbon nanoballs electrochemically stripped at higher potential is much faster than that at lower potential. In particular, as the constant potential moved to a more positive potential of 1.6 V, the current density increased sharply to two times, and the peak of the anode current was about 1.2 mA cm−2 at 50 s. This phenomenon might be attributed to the greater number and the faster growth rate of carbon nanoballs taking place on the surface of GR nanosheets when the constant potential increased to 1.6 V. And as the constant potential reached 1.8 V, the current density of the GR electrode was similar to that of the potentiostatic treated at 1.6 V. It indicated that the growth process of carbon nanoballs at 1.8 V was the same as at 1.6 V. The growth process of carbon nanoballs on GR films always goes through two steps: the rapid growth period and the steady saturation period. During the initial stage, the current density decreases sharply, and the initial rapid growth time is shortened within 100 s or so. It indicates that the nucleation rate in the initial step is much more rapid. This decrease of anodic current depends on the stripping of carbon nanoballs from GR sheets during the growth process. Firstly, GR nanobuds were produced during the induction period on the edge of GR sheets, then graphene nanobuds grew from the edge of sheets, and soon the GR sheets were coated with many nanobuds. Secondly, the secondary nucleation of GR nanobuds occurs already on the GR sheets; the GR nanobuds grew bigger and bigger, swelled to nanoballs, and then stripped from the GR sheets. It indicated that the growth of carbon nanoballs would not be continually increasing but finally level off. After the induction period, the current density keeps steady for a long time, and the exfoliation process of carbon nanoballs enters the saturated growth stage.−2 at 50 s or so, which was nearly three times the current at 1.8 V. The reason may be that the peroxidation of graphene sheets at a higher potential of 2.0 V leads to the formation of a large amount of graphene oxide fragments, and the oxidation current increased significantly compared with that at 1.8 V. Hence, the growth of graphene at 2.0 V was very different from that at 1.8 V. This point can also be deduced from the micromorphology of the GR film at 2.0 V by SEM  scale" fill="currentColor" stroke="none"><path d="M0 440 l0 -40 320 0 320 0 0 40 0 40 -320 0 -320 0 0 -40z M0 280 l0 -40 320 0 320 0 0 40 0 40 -320 0 -320 0 0 -40z"/></g></svg>C stretching vibrations of the sp2 hybridized carbon bond, which was the same as the characterization peak of graphite. As the constant potential increases, the presence of carbon nanoballs like C60 in the GR sheets electrically treated at 1.6 V and 1.8 V is easily indicated in the FTIR spectrum with the appearance of two characteristic peaks at 1400 and 1120 cm−1 as presented in −1 which are correlated with the radial motion of the carbon atoms of C60 and C70 were also detected. Then as the constant potential increased to 2.0 V, the graphene structure changed and new oxygen-containing groups were formed, which may be caused by the peroxidation of the graphene electrode at the higher potential. As shown in −1 was corresponding to the C–O–C stretching deformation of graphene oxide. The reason is the peroxidation phenomenon of the graphene structure caused by higher potential.The Fourier-transform infrared (FTIR) spectra of graphene electrodes at different constant potentials are shown in 3.4d = 0.336 nm), and 54.6°. Hence, the diffraction peaks of GR under an electric field significantly shift to a bigger angle, the crystal distance of GR sheets decreases due to the formation of smaller size graphene. And then, as the constant potential rose, the additional weak peaks at 14.6° and 24.3° were present in the pattern of GR at 1.8 V, and the corresponding crystalline planes were (002), (110), indicating the formation of many carbon nanoballs like C60 due to the incomplete oxidation/intercalation of graphene when the GR electrode is at a relatively higher potential. Meanwhile, a broad peak at 25.1–29.8° was found for the GR samples subjected to potentiostatic treatment of 1.8 V. It can be inferred that graphene nanosheets peeled off with the increase of constant potential. The degree of disorder of the original lamellar crystal structure increased under the effect of an electric field. When the constant potential was more than 1.8 V, the diffraction peak at 28° was obviously widened, and the degree of disorder further improved. Another detectable characteristic peak was observed in the patterns of the GR sample at 2.0 V, corresponding to (001) crystalline planes of graphene oxide (GO), which was located at approximately 10.8°, revealing a few graphene oxides achieved. During the oxidation process of graphene, a strong electric charge intercalated into graphene layers and lots of oxygen-containing groups were formed on the surface of graphene flakes. After the peroxidation of graphene under potentiostatic treatment of 2.0 V, large quantities of graphene fragments fall off, forming GO.The X-ray diffraction (XRD) patterns of the GR electrode at different potentials are shown in 3.524 It is a non-destructive technique that reveals the interactions between individual graphene sheets and functional groups. The Raman spectra of graphene electrodes at different constant potentials are shown in −1 attached and 1580 cm−1, which are the two main characteristic peaks of the Raman spectra of graphene, the D peak and the G peak. In graphene, the G-peak originates from the first-order Raman scattering process of the double simplex plane transverse optical (TO)/longitudinal optical (LO) phonons in the center of the Brillouin zone, and the two sub-peaks in the Stokes and anti-Stokes Raman components of the D-peak are caused by an inelastic scattering event of the emitted photons in the double resonance Raman process or an elastic scattering event of the crystal defects.25 Where the D peak is activated by the edge of a nanosheet with structural defects comparable to or smaller than the laser spot is characteristic of graphene sp2 materials, and the G band is associated with defects in graphene. It is known that I(D)/I(G) is related to the defect density, but not linearly with the defect density, and it varies with the excitation energy. After calculation, the value of I(D)/I(G) increases gradually with the increase of constant potential, and then decreases slightly when the constant potential continues to rise to 2.0 V. It can be seen that the value of I(D)/I(G) is maximum when the constant potential is 1.8 V, i.e., the more obvious the defect of the graphene sheet is at this time. We guess that the reason for the formation of this defect is that carbon nano-budding grows on the graphene sheet under the treatment of constant potential, and as the constant potential rises, the carbon nano-budding grows into nano-spheres, which causes the defect to become more and more obvious. As seen from the curves in Raman spectroscopy, the inelastic scattering of matter to light, has played a central role in the scientific development of graphene and is the most important characterization tool for analyzing graphene-based materials to verify the success of covalent functionalization and to determine the quality of exfoliated graphene.4.in situ growing on the surface of GR sheets as a constant potential of 1.4 V was added to the GR electrode. With the constant potential increasing, the nanobuds grew into the nanoballs, exfoliating from the surface of graphene sheets, whereas the peroxidation of graphene sheets occurred at a higher potential of 2.0 V, leading to the formation of a large amount of graphene oxide fragments. Therefore, the optimal processing parameter of the formation of carbon nanoballs was under the constant potential of 1.8 V for 500 s.In this research, carbon nanobuds can be efficiently generated from graphene under a potentiostatic electric field. The results of this study showed that amounts of nanobuds were Qi Qin and Jing Chen performed experiments and data analysis, Changze Wu and Yixue Wang developed the SEM technique, Fengyi Cao performed the XRD technique, Yunan Li and Zhongzhu Liu performed FTIR experiments, and Meng Song designed the experiments and coordinated the analysis.The authors declare the following financial interests/personal relationships which may be considered as potential competing interests. Qi Qin reports that financial support was provided by Zhongyuan University of Technology. Qi Qin reports a relationship with Zhongyuan University of Technology that includes employment.


The power-law model for composite conductivity is expanded for graphene-based samples using the effects of interphase, tunnels and net on the effective filler fraction, percolation start and “b” exponent. In fact, filler dimensions, interphase thickness, tunneling distance and net dimension/density express the effective filler fraction, percolation start and “b” exponent. The developed equations are assessed by experimented values from previous works. Additionally, the effects of all parameters on “b” exponent and conductivity are analyzed. The experimented quantities of percolation start and conductivity confirm the predictability of the expressed equations. Thick interphase, large tunneling distance, high aspect ratio and big nets as well as skinny and large graphene nano-sheets produce a low “b” and a high conductivity, because they improve the conduction efficiency of graphene nets in the system. Graphene-filled nanocomposites can be applied in the biosensing of breast cancer cells and thus the developed model can help optimize the performance of biosensors. Aoperties , becauseoperties .The conductivity of graphene-based polymer systems has been extensively studied by experimental studies ,30,31. TThe interphase regions are commonly formed in nanocomposites, due to the large interfacial zone amongst polymer medium and nanofiller ,37,38,39The power-law model shows respectable arrangement with the experimented conductivity of graphene products ,52. Nonef” is the filler conduction, “The simple power equation for calculating the conductivity of composites was suggested  as:(1)σ=ectively , althougThis equation only reflects the effects of conduction, amount and percolation start of particles on the conductivity, but it neglects the interphase and tunneling zones, as mentioned. Undoubtedly, these terms affect the effective volume fraction and percolation start of nanofiller, which change the conductivity of whole system.i” are the thicknesses of the nano-sheets and interphase, respectively.The interphase zones of the nanoparticles increase the efficiency of nanofiller, because they can decrease the distance between nano-sheets and contribute to the net. The interphase volume portion in graphene-based nanocomposites  is prediThe effective graphene volume portion in the samples can be calculated by the total sum of the interphase and filler as:The percolation start of 3D unsystematically organized graphite sheets in the nanocomposite was also recommended  as:(4)ϕp“D” is the diameter of the nano-sheets and “d” is the tunneling distance. Nonetheless, D >> d eliminates the role of tunnels in the latter equation as:The interphase regions are formed on both sides of the graphene nano-sheets. In addition, the tunneling spaces comprise the distance between the adjacent nano-sheets. The impacts of interphase and tunnels on the percolation start can be suggested by the development of the above equation as:The predictability of this equation for the percolation start of polymer graphene nanocomposites is examined by the tentative facts in the next section.Assuming the graphene aspect ratio (α = D/t), “The “b” exponent was insufficiently defined in the previous articles for polymer composites and nanocomposites. Some authors have correlated the “b” to particle diameter and distribution ,55. ShaoThe “b” exponent can be defined for graphene samples by the mentioned terms by mathematical operations as:Supposing the impacts of interphase and tunnels on the effective graphene amount (Equation (3)), percolation start (Equation (7)) and “b” exponent (Equation (8)), the power-law model in Equation (1) is:f = 3 × 105 S/m and b = 3, whereas the conductivity mainly falls at b > 4. As a result, the highest nanocomposite conductivity is gained by the uppermost grades of effective filler fraction and graphene conduction as well as by the smallest ranges of percolation start and “b” exponent. Moreover, it is observed that both filler conduction and “b” affect the conductivity more compared to other parameters.The developed model assumes the influence of graphene agglomeration on the conductivity when the average dimensions of agglomerations are considered. The agglomerates of graphene have different sizes and aspect ratios from a graphene layer, which affect the effective graphene concentration (Equation (3)), percolation start (Equation (7)), “b” (Equation (8)) and conductivity (Equation (9)). Therefore, it is possible to take into account the agglomeration of graphene in the conductivity of nanocomposites using the developed model.The obtained equations for percolation start, “b” and electrical conductivity are assessed using the experimental facts of graphene systems from literature.i” and “d” are calculated and observed in i” and “d” show the existence of unlike interphase and tunnels in the examples. The densest interphase (8 nm) and the largest tunnels (10 nm) are witnessed in samples No. 4 and 3, respectively. It should also be indicated that disregarding these parameters results in the incorrect estimation of percolation start. In other words, only the geometries of graphene nano-sheets cannot yield the very small percolation start in nanocomposites, but the interphase around the nanoparticles and the tunneling spaces between neighboring nano-sheets play a role in the percolating of nanoparticles. Accordingly, Equation (6) finely predicts the percolation start in graphene-filled nanocomposites, considering the impacts of the interphase and tunneling zones.The tested conductivity of the examples is applied to the innovative model and the values of the “b” exponent are calculated. The values of the “b” exponent can be applied using Equation (8) to approximate the level of “N”. The calculated “N” for all samples is reported in The stimuli of parameters on the “b” exponent are discussed using Equation (8).i” and “d” in the “b” at t = 2 nm, D = 1 μm and N = 10. The highest value of “b” as 9.5 is observed at ti = d = 2 nm, while “b” decreases to about 4.15 at ti > 10 nm and d > 8 nm. Consequently, the high values of both “ti” and “d” decrease “b”. In other words, thick interphase and long tunneling distance can produce a low “b”, whereas thin interphase and short tunneling distance undesirably enhance it.i” and “d” significantly affect the mentioned terms. The interphase adjoining the nanoparticles can participate in the filler nets; thus, they facilitate the percolation of nanoparticles and enhance the size and compactness of the nets. Likewise, the tunneling spaces between adjacent nanoparticles can contribute to the networking of graphene nano-sheets, because the nanoparticles can form the nets in the presence of tunneling regions [It was mentioned that the “b” exponent inversely depends on the properties of graphene nets in the nanocomposite. Both “t regions ,63. As ai = 4 nm and d = 5 nm are also depicted in “b” exponent at different values of “α” and “N” and average tThe associations of “b” to these factors are expected, due to the direct influence of “α” and “N” on the performance of graphene nets in the nanocomposite. As predicted, a high aspect ratio of the nano-sheets can produce a slight percolation start, which desirably affects the magnitudes of the nets ,64. In fThe calculations of the “b” exponent at unlike arrays of “t” and “D” are also seen in Skinny and large nano-sheets beneficially manage the size of nets in the products, because they cause a poor percolation start and also produce dense nets. At a constant volume of nanoparticles, thin nano-sheets show a high number. Therefore, the nanocomposites containing thinner nano-sheets contain a larger number of nanoparticles. Additionally, the contacts between larger nano-sheets are more than those of short ones. Thus, skinny and big nano-sheets can develop the attributes of filler nets in the nanocomposite; therefore, the developed equation accurately forecasts the “b”.f = 105 S/m is considered.The impact of the parameters on the conductivity of graphene is evaluated by the developed equation (Equation (9)) based on interphase and tunneling regions. In all calculations, σi” and “d” at t = 2 nm, i = 12 nm and d = 10 nm. However, ti < 8.5 nm and d < 5 nm induce very little conductivity adjacent to 0. So, profuse interphase and high tunneling distance can harvest a high conductivity. Instead, thin interphase and short tunnels cannot significantly improve the conductivity.As mentioned, the interphase and tunnels take part in the nets because they surround the nanoparticles. Therefore, profuse interphase and large tunnels significantly increase the net size/density, which positively improves the conductivity. It can be said that a thick interphase and a large tunneling space can involve more nanoparticles in the conductive nets. In contrast, thin interphase and short tunneling distance negligibly manipulate the net size/density. So, the advanced model shows reasonable impacts of interphase deepness and tunnel size on the nanocomposite’s conductivity. However, it should be said that a very large tunneling distance between adjacent nano-sheets weakens the tunneling effect, producing insulation.i = 4 nm, The impacts of “α” and “N” on the conductivity of the system at t = 2 nm, tThe optimistic role of the aspect ratio in the sample’s conductivity is attributed to its impacts on the percolation start and net dimensions. A high aspect ratio results in a low percolation start in the graphene nanocomposites, as mentioned. Additionally, a high aspect ratio causes a big surface zone, which creates large nets. A low percolation start boosts the conductivity of the system, as seen in i = 4 nm, The thin and large nano-sheets control the percolation start and net scale in the nanocomposite based on Equations (6) and (8). Additionally, polymers are frequently insulated and the conductive nanofillers handle the whole conductivity. Since the conductivity of the nanocomposite depends on the percolation level and the net dimensions, skinny and large nano-sheets can play an optimistic role in the conductivity. In fact, the thin and large nano-sheets can cover a high fraction of the nanocomposite, which produces big nets and high conductivity. Alternatively, the efficiency of dense and small nano-sheets is insignificant, because they produce small nets, which cannot effectively transfer the electrons. As a result, the optimistic effects of skinny and large nano-sheets on the conductivity of samples are meaningful.The power equation for composite conductivity was developed for graphene-filled samples, determining the effects of interphase, tunnels and net dimension/density on the effective filler fraction, percolation start and “b” exponent. Additionally, the measured records of percolation start and conductivity were applied to confirm the predictability of the established equations. A high conductivity is found using a large filler amount, slight percolation start, significant filler conduction and small “b”; however, the impact of the filler conduction and the “b” exponent is more significant compared to the other parameters. The experimental data of percolation start have good arrangement with the predictions. So, the interphase depth and tunneling size play a main role in the percolation value of graphene in the system. Moreover, the innovative model adequately predicts the conductivity of the examples. Generally, thick interphase, large tunneling distance, high aspect ratio and dense nets as well as thin and big graphene nano-sheets produce a low “b” exponent. In addition, these factors cause high conductivity, suggesting that they considerably increase electron transfer in the system. This model was only developed for polymer graphene nanocomposites. Since graphene-filled nanocomposites can be used in the biosensing of breast cancer cells, the developed model can help enhance the performance of biosensors.


However, 2D materials were only produced on limited archetypal substrates by chemical vapor deposition approaches. Reliable after-growth transfer techniques, that do not produce cracks, contamination, and wrinkles, are critical for layering 2D materials onto arbitrary substrates. Here we show that, by incorporating oxhydryl groups-containing volatile molecules, the supporting films can be deformed under heat to achieve a controllable conformal contact, enabling the large-area transfer of 2D films without cracks, contamination, and wrinkles. The resulting conformity with enhanced adhesion facilitates the direct delamination of supporting films from graphene, providing ultraclean surfaces and carrier mobilities up to 1,420,000 cm Reliable transfer techniques are critical for the integration of 2D materials with arbitrary substrates. Here, the authors describe a method to transfer 4-inch and A4-sized defect-free graphene films onto rigid and flexible substrates with controllable conformal contact, leading to improved electrical properties and uniformity. However, a critical challenge has emerged in the lack of reliable after-growth transfer techniques for layering 2D membranes onto arbitrary substrates for large-scale technological applications6. Currently, the most significant issues associated with the 2D materials transfer arise from cracks, wrinkles, and interfacial contamination9 generated during the transfer that compromises the homogeneity and electronic performance, such as carrier mobility. Additionally, such difficulties grow exponentially with increasing film size7.Many efforts have resulted in the breakthrough in the chemical vapor deposition (CVD) fabrication of large-area graphene10. The key to achieving crack-free transfer is the continuous mechanical support for graphene during transfer. Such support can be supplied by introducing supporting films and the conformal contact between graphene and the target substrate12. In this regard, various supporting foils have already been introduced13. However, after the removal of supporting foils, non-conformal adherence of graphene onto the target substrate would make the graphene free-standing in some regions; such free-standing graphene would be torn by the interfacial forces in the subsequent removal of the transfer medium. As a consequence, a universal approach to realizing conformity between substrates and graphene is critically needed to achieve crack-free transfer.The flexibility and thinness of graphene make it susceptible to mechanical deformation and damage in conventional CVD graphene film transfer processes14. Therefore, the removal procedure generates organic waste solvents and leaves unavoidable contamination on surfaces as well as metals and etchant residues15 in etching-based delamination, which degrades graphene quality14. Polymer-free techniques are efficient for avoiding contamination, which, however, fails in large-area transfer16. Hence, methods for contamination-free transfer that do not require the use of organic solvents are in high demand for large-area transfer.In addition, the removal of supporting polymer films, such as poly (methyl methacrylate) (PMMA), is usually insufficient and requires aggressive chemical treatmentsTg) polymers  into PMMA, we can achieve the conformal contact between graphene and destination substrates, and the controllable conformal contact enables us to achieve the transfer of 4-inch graphene single-crystal wafers on Cu wafers17 and A4-sized graphene films on Cu foils13 (two research hotspots of CVD graphene18) onto rigid SiO2/Si and soft polyethylene terephthalate (PET) substrates, respectively, free of cracks, wrinkles, and contamination, which contribute to the improved electrical performance. Furthermore, the conformal contact improves graphene-substrate adhesion and allows for direct delamination of supporting films without producing contamination.Herein, by adding oxhydryl groups-containing volatile molecules (OVM)  or low-glass-transition-temperature  images , along with a side peak arising from the higher residue particles  Fig. 28. Waferoff Fig. . In addip-doping transport behavior of graphene26. The presence of air gaps was confirmed by the large difference in height between graphene and the substrate in AFM images  is 29:According to the stress-separation relationship in contact mechanics, the resulted conformity with the reduced separation distance between graphene and substrates would engineer the adhesion, enabling the mechanical delamination of supporting films. In the case of graphene on SiOons Fig. . Therefo29 , which is an indicator of strain and doping level  to exclude substrate interference31, and the obtained carrier mobilities range from 70,000 to 120,000 cm2 V−1 s−1 at room temperature and from 800,000 to 1,420,000 cm2 V−1 s−1 at 4 K  and high-intensity ratio of 2D band to G band (~8) in encapsulated graphene  vertical heterostructure via layer-by-layer transfer  intensities confirmed the successful transfer of MoS2 onto graphene46  were utilized as the epitaxy substrates for the preparation of single-crystal Cu. Before the deposition, sapphire wafer was annealed in a pure oxygen atmosphere for 6 h at 1020 °C in atmosphere pressure to achieve an oxygen-terminated surface to reduce the density of in-plane twin boundaries in Cu films. Subsequently, a 500-nm-thick Cu film was deposited on sapphire wafer by radio frequency (RF) sputtering equipment . Then, to prepare single-crystal Cu (111), Cu/sapphire wafer was annealed at 1020 °C for 2 h in atmosphere pressure with 1000 sccm Ar and 100 sccm H2. Subsequently, 100 sccm CH4 (0.1% diluted in Ar) was introduced to initiate the graphene growth, and graphene wafer with full coverage could be obtained after 2 h. After graphene growth, the system was cooled down to room temperature under the same gas flow.The Cu (111) wafer was first heated to 1020 °C in an atmosphere-pressure CVD system with 1000 sccm Ar and 100 sccm H90Ni10 (111) wafer was first heated to 1020 °C in atmosphere-pressure CVD system with 1000 sccm Ar and 400 sccm H2. Subsequently, 2 sccm CH4 was introduced to initiate the graphene growth, and graphene wafer with full coverage could be obtained after 2 h growth. After the graphene growth, the system was cooled down to room temperature under the same gas flow.The Cu2 for 30 mins. Then, the growth of graphene film was initiated by the introduction of 1 sccm CH4. After 1 hour growth, the system was cooled down to room temperature under the same flow.The large-area graphene films were grown using the low-pressure CVD system. The Cu foil  was loaded into the tube furnace as the growth substrate. The sample was first heated to 1020 °C with 500 sccm Ar, followed by annealing with 500 sccm H2/Si substrates by the commercial laminator at the temperature of 100 °C. Heat treatment of graphene films at a temperature of 120 °C was conducted in oven to initiate the deformation of supporting films and the conformal contact. Note the heat treatment temperature can be reduced with longer heating time. Subsequently, supporting films/TRT was mechanically peeled off from graphene to obtain a clean graphene surface. The time consumed in the transfer is listed in Supplementary Table First, OVMs including cedrol , alpha-terpineol , linalool  and (-)-borneol  were dissolved in n-heptane (Tianjin Concord Technology) (10 wt%), and the solutions were subsequently spin-coated on 4-inch graphene films grown on single-crystal Cu wafers. Thereafter, PMMA  was spin-coated onto as-deposited OVMs layers to form a composite film by evaporation of the anisole . Note that the anisole can also readily dissolve OVMs. Second, TRT  is laminated onto the supporting films with a commercial laminator at room temperature  with a laminating rate of 2 cm per second. Subsequently, bubbling-based delamination of graphene from Cu is conducted by the customized bubbling-delamination equipment  and PMMA  layer-by-layer as the supporting films (15 mm/s) by a commercial blade coater (1811 BEVS). Subsequently, TRT was laminated onto the supporting films by a commercial laminator  at room temperature with a laminating rate of 2 cm per second. Subsequently, bubbling-based delamination of graphene from Cu was conducted by the customized bubbling-delamination equipment  was sonicated (28 kHz) for 30 mins and filtered through a commercial filter to avoid large particles. Subsequently, 4.5 wt% of Dimethyl sulfoxide (DMSO)  and Zonyl FS-300  were added into PEDOT:PSS solution, and mixed overnight at room temperature. The DMSO was used to improve the electrical conductivity of PEDOT:PSS solutions and the Zonyl was used as a surfactant in mixed solution. The mixed solution was spin-coated onto graphene on PET at 1000 rpm for 60 s, followed by heating at 80 °C for 5 mins for the membrane formation.3 powder  in the heating center of the furnace (Lindberg/Blue M HTF55347c). The sulfur powder  was placed in a quartz boat at the upper stream, 30 cm away from the substrate. Monolayer MoS2 was grown at 750 °C for 8 min by ambient pressure CVD, and 80 sccm Ar was used as carrier gas. The same procedures (OVMs-modified supporting films) were used in the transfer of MoS2 onto pre-transferred graphene to fabricate the vertical heteostructure.Commercially available polycrystalline gold foil  was cleaned by ultrasonication in hydrochloric acid (20 wt%) and acetone, respectively. Then the cleaned Au foil was annealed at 950 °C for 5 h. The annealed Au foil was faced downward to the MoO2/Si substrates, followed by the direct peeling of supporting films off the substrates.The Cu wafer was used as the sacrificial layer for transferring the Cr/Au electrodes. Wafer-scale patterning on Cu wafers was conducted by laser direct writing (Heidelberg MLA-150) . Subsequently, the 5 nm Cr layer was deposited on Cu wafers, followed by the deposition of 50 nm Au using the e-beam evaporator (Angstrom Engineering nexdep). After the lifting off, coating of OVMs and PMMA was conducted to form supporting films. Subsequently, Cu wafer was etched away, leaving the Cr/Au electrodes on supporting films. After the rinsing and drying of the films, the films were laminated onto substrates such as PET and SiOFirst, the PMMA solution  was spin-coated onto one side of the graphene/Cu sample with spin-coating rate of 1000 rpm for 60 s and dried for 3 mins on a hot plate at the temperature of 80 °C. Oxygen plasma was used to etch graphene on the back side of the sample. Subsequently, we laminated the TRT onto PMMA film after the curing of PMMA. Then, electrochemical bubbling-based delamination of graphene from Cu was conducted, followed by rinsing and drying of the TRT/PMMA/graphene. Then we laminated graphene onto target substrates in a dry environment. After the lamination, heat treatment of the TRT would significantly reduce the adhesion energy between TRT and PMMA, which would leave the PMMA/graphene onto the target substrates. Finally, the PMMA was removed by soaking the sample in the acetone bath, and graphene was dried with compressed nitrogen gas.2/Si substrate at room temperature and then was dried overnight to reduce the water trapped between graphene and substrates. Finally, the PMMA was removed by soaking the sample in the acetone bath and dried with compressed nitrogen gas.First, the PMMA solution  was spin-coated onto one side of the graphene/Cu sample with a spin-coating rate of 1000 rpm for 60 s and dried for 3 mins on a hot plate at the temperature of 80 °C. Oxygen plasma was used to etch the graphene on the back side of sample. Subsequently, sodium persulfate  solution was used to etch Cu foil, and the PMMA/graphene film was floated on the surface of the solution. The PMMA/graphene film was washed with distilled water several times to remove the etchant residue. After the rinsing of the PMMA/graphene film with distilled water, the PMMA/graphene film was scooped out by a SiO2H-PMMA is purchased from Polymer source company (production number #P100226-d5 PMMA) with Mn = 820,000 and Mw = 1,500,100. Annealing experiments were performed in the chamber of the ToF-SIMS spectrometer  before characterization. The samples were analyzed at 25 °C after annealing at 100 °C for 1 h. ToF-SIMS spectra were acquired at the annealing temperature using a Bi3+ beam operating at 25 keV. The scanning area was 200 μm × 200 μm with an acquisition time of 40 s. Negative ion spectra were collected for each sample. The software used for peak analysis was SurfaceLab 6.0 from ION-ToF.The Optical microscopy images were obtained with a Nikon Olympus LV100ND. Raman spectra were obtained with LabRAM HR-800 with 532 nm laser. Optical transmittance spectra were collected by a Perkin-Elmer Lambda 950 UV-vis spectrophotometer. AFM characterization of graphene was carried out on Bruker dimension icon microscopy using the Scanasyst mode. The sheet resistance was measured using a four-probe system (CDE ResMap 178) based on the four-point probe method to eliminate contact resistance. Four metal probes were aligned in a line at intervals of 1 mm. White Light Interference images were conducted using a Nikon White Light Interferometry (BW-S501).2/Si wafer was probed by taking the photographs of entire graphene wafer, while a commercial scanner was used to enhance the contrast difference to visualize graphene on transparent PET substrates for probing Macro-intactness. After taking the photos, the ratio of pixels was counted with different contrast to obtain the macro-intactness. OM images with 5× and 50× magnifications were taken to probe the micro-intactness: the twenty-five OM images with 5× magnifications were taken over transferred graphene  and we can obtain an average value. Subsequently, the OM images with 50× magnification were taken by randomly zooming in. After obtaining the values of macro-intactness and the micro-intactness using 5× and 50× magnification OM images, the three values were multiplied to obtain the final intactness.Macro-intactness of graphene on SiO2/Si at 52 °C. The “pick up” is possible because the van der Waals forces between hBN and the graphene are relatively stronger than that between SiO2/Si and the graphene. Subsequently, the graphene/hBN/PPC/PDMS stack was brought into contact with another hBN flake by releasing graphene/hBN at 70 °C from PPC surfaces, resulting the formation of the final hBN/graphene/hBN heterostructure. Electron-beam lithography and reactive ion etching (RIE) were employed to pattern the stack into a Hall bar geometry. After the RIE etching, Cr/Au (3/50 nm) electrodes were deposited by electron-beam evaporation for forming one-dimensional contacts.To probe electronic quality and exclude the interference from substrates, monolayer graphene after the transfer was encapsulated by two flakes of around 50 nm-thick hBN crystals. In detail, an hBN flake was picked up at 52 °C by a PPC/polydimethylsiloxane (PDMS) stack on a glass slide, which was attached to a micromanipulator. The as-formed hBN/PPC/PDMS stack was then used to pick up the graphene from the SiOIds with a root mean square amplitude of 1 μA at 23.33 Hz was applied between the source and drain terminals. Meanwhile, the four-point longitude voltage drop Vxx and transverse voltage drop Vxy were measured with lock-in amplifiers. The charge density tuning in the graphene channel is achieved by applying different back gate voltage (Vbg). The device was tested in Argon inertial environment (glovebox at the temperature of 300 K) and vacuum environment (cryostat at a temperature lower than 100 K). Rxx is the longitude resistance, which can be obtained according to the equation: Rxx = Vxx/Ids, and Rxy is the Hall resistance which can be obtained by Rxy = Vxy/Ids. The longitude resistivity (ρxx) can be calculated from ρxx = Rxx × W/L, where W is the width of the conducting channel, L is the length of the channel between the probed contacts. The longitude conductivity (σxx) can be obtained via σxx = 1/ρxx, while the Hall carrier density (n) can be determined by equation: n = B/(eRxy), where e is the elementary charge. Based on the Drude model, mobility (µ) can be estimated from the linear regions in the transfer curve .The electrical properties of the fabricated devices were characterized by the conventional lock-in technique. An AC current rve Fig.  accordin2/Si with marks for alignment. each graphene sample was etched into a Hall bar geometry using a PMMA etching mask (PMMA 950 K A4 @ 4000 rpm) designed by electron-beam lithography (EBL) (Raith 150 2nd) and plasma etching with air (Diener Pico). After using EBL to design a PMMA mask, Cr/Au (10/40 nm) electrodes were deposited on the samples using an electron-beam evaporator (Angstrom Engineering nexdep) and then a standard metal lift-off technique. The arrays of Hall bar devices on 4-inch transferred graphene were fabricated by maskless laser lithography system (Heidelberg MLA-150) with a photoresist . Electrical characterization at room temperature was performed in a vacuum probe station (Lakeshore CRX-VF) with a semiconductor characterization system .Hall bar devices were fabricated on the graphene/SiORaman spectra were obtained with Horiba LabRAM HR-800 with 532 nm and 633 nm laser. AFM (Bruker dimension icon) was used to characterize the morphology of the graphene samples. The element analysis was performed by XPS . The roughness of as-transferred graphene and the thickness of OVMs and Polymer films were measured by using the white light interferometer (BW-S501). The optical transmittance of graphene was measured using a UV-VIS-NIR Spetrometer (Perkin-Elmer Lambda 950)2/Si layer contacts with SiO2-supported graphene. The top SiO2 layer approaches the supported graphene, and the adhesion stress could be obtained at different separation distances. The coarse-grained model of the SiO2 layers and the SiO2/Si substrates was used according to the literature. The interaction between the carbon atoms and the coarse-grained SiO2 particles was presented by Lennard-Jones potential 2 particles of the substrate were constrained to maintain its surface corrugations. The geometrical parameters of the substrates and the graphene sheets were obtained from the AFM images of bare substrates and supported graphene on substrates. In the case of graphene on PET, there is no reliable potential for calculating the van der Waals interaction. Therefore, we approximated the van der Waals interaction by adding a multiplier A series of MD simulations were performed to calculate the adhesion force through LAMMPS package. The schematic diagram is shown in Fig. Supplementary information