Graphene Oxide Layers Research Articles

The Effect of Graphene Oxide on Optical, Ferroelectric, and Catalytic Properties of Protein-Encapsulated ZnSe Nanocomposite

To explore the effect of graphene oxide (GO) on optical, ferroelectric, and catalytic properties of the protein-encapsulated ZnSe nanocomposite, we have prepared BSA-encapsulated ZnSe (BSA-ZnSe) nanocomposite and graphene oxide integrated BSA-encapsulated ZnSe (GO/BSA-ZnSe) nanocomposite samples. The ZnSe nanoparticles within these nanocomposites exhibit a highly crystalline zincblende structure with an average size of 3.7 nm. Transmission electron microscopy studies confirm the successful integration of GO in the BSA-encapsulated ZnSe sample. Fourier-transform infrared spectroscopy results suggest that the interactions between ZnSe nanoparticles and BSA, likely facilitated by the amide and hydroxyl groups present in BSA. Optical studies showed that the addition of GO influenced the emission spectra towards a red shift, which is attributed to the conductive influence of graphene oxide. The ferroelectric properties indicated that the graphene integrated ZnSe nanocomposite exhibited high remanence and coercivity due to the interaction of semiconductive ZnSe with GO layers. In terms of catalytic activity, the GO/BSA-ZnSe nanocomposite exhibited better performance compared to the BSA-ZnSe nanocomposite.These results highlight the significant influence of graphene oxide on the optical, ferroelectric, and catalytic properties of the BSA-encapsulated ZnSe nanocomposite.

Plasma-Modification of graphene oxide for advanced ammonia sensing

The exceptional tailoriability of electrical properties in reduced graphene oxide (rGO) is a pivotal factor in unleashing its advanced gas sensing capabilities. Amidst various chemically/thermally-driven techniques, plasma reduction emerges as the fastest method with the potential for scalable treatment. This paper demonstrates a controlled plasma-enabled approach for swift and green surface reduction of graphene oxide (GO) films, specifically tailored for room-temperature ammonia (NH3) detection at ppm levels. Employing a mild hydrogen plasma treatment on a thin GO layer deposited on copper electrodes by drop casting, we were able to tailor the sensor’s sensitivity and reversibility due to the great impact of treatment time. The GO reduction experiments were conducted in a low-pressure mild hydrogen plasma discharged at 100 W, and the treatment time varied between 10 and 240 s. Structural and chemical analyses reveal an instantaneous reduction in oxygen content, dropping from approximately 30 to 20 atomic percentages within the initial 20 s. Sensitivity and recovery trade-offs are explored for different treatment durations, with the ‘rGO - 20 s’ sensor demonstrating the highest sensitivity at 23.9 % (100 ppm) and 47.1 % (1049 ppm) of NH3, albeit with a recovery time approximately four times longer than the ‘240s-rGO’ sample. This double-play behavior, attributed to chemisorption-dominated and physisorption-dominated interactions of NH3-rGO, elucidates the sensitivity and recovery time dynamics. Proposing a scalable, environmental-friendly and room-temperature H2-plasma reduction process enables one of the fastest approaches for designing advanced rGO sensors with controllable sensing behaviour towards ammonia.

Amine-functionalized metal organic framework@graphene oxide as filler in PAEK-containing carboxyl group membrane for ultrafiltration with ultra-high permeability and strong fouling resistance

Achieving high fouling resistance and permeability using membrane separation technology in water treatment processes remains a challenge. In this work, a novel mixed matrix membrane (PAEK-COOH/UiO-66-NH2@GO) with superb fouling resistance and high permeability was prepared by the nonsolvent induced phase separation method, by in-situ growth of UiO-66-NH2 on graphene oxide (GO) layer, and by preparing hydrophilic poly(arylene ether ketone) (PAEK) containing carboxyl groups (PAEK-COOH). On the basis of the structure and performance analysis of the mixed matrix membrane (MMMs), the maximum water flux reached 591.25 L·m–2·h–1 for PAEK-COOH/UiO-66-NH2@GO, while the retention rate for bovine serum albumin increased from 85.40% to 94.87%. As the loading gradually increased, the hydrophilicity of the MMMs increased, significantly enhancing their fouling resistance. The strongest anti-fouling ability observed was 94.74%, which was 2.02 times greater than that of the pure membrane. At the same time, the MMMs contained internal amide and hydrogen bonds during the preparation process, forming a cross-linked structure, which further enhanced the mechanical strength and chemical stability. In summary, the MMMs with high retention rate, strong permeability, and anti-fouling ability were successfully prepared.

Self-assembled graphene oxide thin films deposited by atmospheric pressure plasma and their hydrogen thermal reduction

This work uses an atmosphere-pressure plasma jet to obtain thin, homogeneous graphene oxide coatings. The films consisted of self-assembled graphene oxide (GO) layers, which were reduced by heat treatment under a reductive hydrogen atmosphere to obtain a reduced graphene oxide film. The electrochemical and photoelectrochemical analyses show that electrical conductivity increases after the reduction process; meanwhile, this process eliminates the p-type photoactivity of the graphene oxide film. The reduced graphene oxide X-ray diffraction pattern revealed the elimination of the signal at 2θ = 11° initially found in the graphene oxide film. The C1s and O1s high-resolution XPS analyses of the reduced graphene oxide film reveal a pronounced increase in the graphitic-like carbon (sp2), whereas a decrease in the organic-like carbon (sp3) and oxygenated species, such as C-OH, C-O-C, CO, and OCOH, initially found in the graphene oxide film.

Investigation of the pH-mediated fabrication process of pure and polyethyleneimine-crosslinked graphene oxide membranes for desalination and heavy metal ion separation

Graphene oxide (GO) membranes have been extensively investigated and employed in separating various ions and molecules due to their superior physicochemical properties. However, the inconsistency in their pore structure, difficulty in the precise tuning of their d-spacing, and instability in aqueous solution – especially at extreme pH values – might hinder their separation efficiency. In this research, we systematically investigated the pH-mediated fabrication process of graphene oxide membranes and evaluated the properties of the resulting membranes. Findings from scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses show that a higher fabrication pH results in a thicker GO layer and an enlarged d-spacing due to the deprotonation of the GO's carboxyl groups. Furthermore, pH-assisted crosslinking between polyethyleneimine (PEI) and GO sheets were facilitated and the chemical analysis results suggest that in acidic environments, the dominant reaction involves C–N bond formation at the basal plane, whereas under alkaline conditions, N–CO (amide) bond formation at the edges is more prevalent. This, in return, accordingly shifted the trend in SEM and XRD, where a thinner GP layer and a decreased d-spacing were observed at a higher fabrication pH due to the deprotonation of the incorporated PEI's amine groups. These findings contributed to the nanofiltration (NF) performance of the membranes against different inorganic salts and heavy metal ions. It was discovered that the GPpH11 membrane formed at pH 11 has the highest Pb2+ rejection of >95%, making it a suitable material for heavy metal ions removal.

Green synthesis of carbon quantum dots from teak leaves biomass for in situ precipitation and regenerative-removal of methylene blue-dye.

The objective of this study was to completely eliminate environmentally harmful cationic organic dye from aqueous solutions using the one-step ultrasonication method, renowned for its energy efficiency, user-friendliness, and minimal requirement for chemical resources, making it particularly suitable for large-scale applications. To achieve effective environmental remediation, we employed carbon dots derived from teak leaf biomass (TBCDs) layered with graphene oxide. We conducted a thorough characterization of the TBCDs using UV-vis spectroscopy (with absorption peaks at λmax = 208 and 276nm), FTIR spectroscopy (confirming the presence of various functional groups including -OH, -CH, C = O, COO-, C-O-C, and = C-H), Raman spectroscopy (with bands at 1369cm-1 (D-Band) and 1550cm-1 (G-Band), and an intensity ratio (ID/IG) = 0.88, indicating structural defects correlated with the sp3 hybridization sites on the TBCDs), XRD analysis (indicating an amorphous nature of particles), HRTEM imaging (showing homogeneous dispersal of TBCDs with typical sizes ranging from 2 to 10nm), FESEM analysis (showing a flat surface and minuscule particles), and Zeta potential analysis (revealing a surface charge peak at -51.0mV). Our adsorption experiments yielded significant results, with a substantial 50.1 % removal rate and an impressive adsorption capacity of 735.2mg g-1. Theoretical adsorption parameters were rigorously analyzed to understand the adsorption behavior, surface interactions, and mechanisms. Among these models, the Langmuir isotherm in conjunction with pseudo-second-order kinetics provided an exceptional fit (with R2 values closer to 1) for our system. The Gibbs free energy (ΔG) was found to be negative at all temperatures, indicating the spontaneity of the reaction. Regarding mechanism, electrostatic attraction ((+ve) MB dye + (- ve) TBCDs), π-π stacking adsorption facilitated by the graphitic structure, formation of multiple hydrogen bonds due to polar functional groups, and a pore-filling mechanism wherein the cationic MB dye fills the pores of TBCDs with graphene oxide layers, forming an adduct were identified. Furthermore, we demonstrated the regenerative capacity of our system by effectively extracting and recovering the MB dye (with a regeneration rate of 77.1%), utilizing ethyl alcohol as the solvent. These findings not only provide valuable insights into the adsorption capabilities of TBCDs but also highlight the potential of our approach in the recovery of expensive cationic organic dye compounds from polluted environments.

Calcium-facilitated adsorption and precipitation of bacteria on the graphene oxide surface

Efficient removal of bacteria from aqueous environments is a hot research topic. Graphene oxide (GO) has been widely used due to its antimicrobial properties and high surface activity. However, GO alone could not remove bacteria from the aqueous environment through aggregation and precipitation. In this study, CaCl2 (Ca2+) was introduced into the process of bacterial removal by GO due to the negative charge on the surface of the removed bacteria (Sporosarcina pasteurii). The introduction of Ca2+ leads to the re-accumulation of GO layers, and the proportion of oxygen-containing functional groups in GO increases significantly. AFM and zeta potential results indicate a reduction in the negative charge on the GO surface in the presence of Ca2+, which reduces the electrostatic repulsion to bacteria. This leads to a gradual increase in the attractiveness of the GO surface and the adsorption of more bacteria. Ca2+ acts as a bridge, facilitating the sedimentation of GO and bacteria, resulting in the removal of bacteria from the water environment. The removal efficiency of GO against bacteria increased as the concentration of Ca2+ increased.

Investigating the thermally induced p-n transition in reduced graphene oxide layers exposed to hydrogen sulfide

To investigate the origin of the p-n transition observed in graphene-based materials for chemical sensors, we developed sensing layers made of chemically reduced graphene oxide (rGO), prepared from graphene oxide (GO) using citrate as a reducing agent. We focused mainly on the thermally induced p-n transition when the sensing layers are exposed to H2S at a specific temperature. The rGO sensing layers are prepared through drop casting on interdigitated electrodes. Scanning electron and transmission electron microscopes allow the characterization of the rGO structure, while FTIR, X-ray photoelectron spectroscopy, and electrical characterization have revealed the reduction efficiency. The p-n transition occurs between 80 °C and 90 °C, whatever the resistance range and the exposition history to H2S. The temperature-dependent transition, which starts around 80–90 °C, is reversible if the temperature is kept below 80 °C, i.e., the rGO remains p-type material. When experiments are performed at a temperature above 90 °C, the transition from p-type to n-type takes place, and the n-type persists, showing an irreversible transition. The transition starts gradually at 80 °C during lower concentration exposure and ends at high concentration. Finally, the results show that temperature and H2S contribute to the inversion of the initial charge carriers.

Graphene oxide: Synthesis and laser spectroscopy approach

Nanotechnology research offers advancements in materials and industrial uses such as nano-electronics, medical sciences, fuel, biology, and technological innovation. The most often employed nanomaterial is Graphene oxide (GO), which has been regarded as a dominant progenitor for many specialized industries. The current work aims to establish a new, cost-effective, easy, and straightforward GO synthesis method. Laser spectroscopy and even traditional tools have been utilized for characterization. The prepared GO has been confirmed by XRD and FT-IR spectroscopy. Laser spectroscopy based on confocal microscopes like Raman micro-spectroscopy and fluorescence lifetime imaging microscopy (FLIM) has been used to ensure the synthesis of GO. Also, it could help in the detection of the prepared layer thickness. Raman spectroscopy detects the number of GO layers, which is one on average, while the Raman mapping shows a good distribution of GO on the substrate. Based on excitation with a 445 nm pulsed laser, FLIM shows that mono GO layers cover most of the surface while only a tiny area contains more than a single layer. The novel aspect of this work is the method of preparation and the way of utilizing both FLIM and Raman to detect the number of GO layers. The prepared GO could be used in many applications like solar cells and filtration.

A convenient approach to manufacturing lightweight and high-sound-insulation plywood using furfuryl alcohol/multilayer graphene oxide as a shielding layer

ABSTRACT With the requirement of green construction, the building envelope system urgently needs lightweight material with high sound insulation performance. In this study, a kind of plywood with furfuryl alcohol/multilayer graphene oxide (FA/MLGO) layer was prepared by lamination. The four-microphone impedance tube method measured the sound insulation to evaluate optimal process parameters. At the same time, the acoustic impedance, damping performance, interface microstructure, and chemical components were characterized to discuss the sound insulation mechanism of FA/MLGO as a shielding layer. It showed that the weighted transmission loss of plywood with different FA/MLGO layers was enhanced, and acoustic impedance increased while the acoustic radiation damping coefficient decreased. In addition, considering economic costs, the optimal preparation process was three layers with 0.5 wt.% MLGO concentration and 50 wt.% FA concentration, followed by curing for three h. The surface properties, micromorphology, and chemical composition results indicated that FA/MLGO layer formed more complex sound propagation paths in the plywood, thereby increasing the loss of sound energy inside. Thus, the sound insulation of the plywood was improved.

Mechanisms of methanol detection in graphene oxide and conductive polymer active layers for gas sensing devices

The admixture of PEDOT:PSS with Graphene Oxide (GO) in precise proportions achieves a substantial reduction in electrical resistivity, thereby augmenting its suitability as an electrode in organic devices. This study explores the electrical and morphological attributes of commercial PEDOT:PSS and chemically synthesized aqueous PEDOT ink when both are combined with GO. The investigation extends to the application of these conductive inks as active layers in flexible methanol sensing devices. Notably, a resistivity minimum is observed in the case of GO:PEDOT:PSS 78%, while the highest response to methanol is attained with GO:PEDOT:PSS 68%. To establish a theoretical underpinning for these findings, and to understand the interaction between gas/vapors with nanostructured materials, a model rooted in Kirchhoff’s Circuit approach is developed, with the aim of elucidating the factors behind the resistivity minimum and response maximum at distinct specific mass ratios between PEDOT and GO. Calculating the equivalent resistivity and response of the systems, the positions of minimum and maximum points are in agreement with the experimental data. Furthermore, the influence of PSS in the samples is examined, unveiling diverse interaction mechanisms between methanol molecules and the active layer, resulting in varying signals during the exposure to alcoholic vapor. The theoretical model is subsequently applied to these systems, demonstrating qualitative and quantitative agreement with the experimental results.

Graphene oxide-decorated hyrogel inverse opal photonic crystal improving colorimetric and fluorescent responses for rapid detection of lipocalin-1

In this paper, the colorimetric and fluorescent biosensors prepared from polyethylene glycol diacrylate (PEGDA)-based inverse opal photonic crystal (IOPC) decorated with graphene oxide (GO) (termed as GO-modified PEGDA-based IOPC) have been explored for simple and rapid semi-quantitative and quantitative detections of biomarker lipocaline-1 (LCN1) in tear at low level, respectively. We found that only after the concentration of GO (CGO) was sufficiently high to create a thin GO layer due to intermolecular interactions between neighboring GO molecules on the PEGDA surface, the red-shift of the reflection peak position (λstb) became effective. This widening of the shift in λstb became significant when GO-modified PEGDA-based IOPC was selectively attached with LCN1 via the immunoassay, because the attachment with LCN1 caused a reverse shift in λstb. Correspondingly, the visualizable photonic color could vary in wider range depending on the concentration of LCN1 (CLCN1), from orange color of blank solution to light blue color of solution containing LCN1 at CLCN1 of 0.06 mg/mL using CGO = 2.5 mg/mL. For quantification, CGO and enrichment time of LCN1 were optimized for getting the maximum fluorescence microscopy intensity. The diagram for the relationship between fluorescence intensity and CLCN1 showed various advantages of GO-modified PEGDA-based IOPC over non-GO-modified PEGDA-based IOPC. Those were higher fluorescence intensity, wider linear range and higher detection sensitivity. Thus, our results revealed potential applications of GO-modified PEGDA-based IOPC in screening patients with diabetic retinopathy (DR) in early stage.

Hybrid SERS substrate based on cotton swab for sensitive detection of organic molecules

For the last two decades, the development of substrates for Surface Enhanced Raman Spectroscopy (SERS) has been continuously pushed for better performances. In this research, we designed SERS substrates with better detection capability and more efficient sample collection. In particular, morphology-controlled Ag nanoparticles were deposited onto cotton swab (cotton Q-tip), followed by a thin cover layer of graphene oxide by the dip-coating method. The graphene oxide overlay was expected to not only protect Ag nanoparticles from degradation by the environment but also contribute to sample adsorption and signal enhancement. To demonstrate the performance of the SERS substrates, different concentrations of Rhodamine B as low as 10–10 M were successfully detected and the enhancement factors were estimated to be 3 × 1010–5 × 1010. It is our expectation that these cotton swab-based substrates will contribute to our ongoing efforts toward low-cost, high-efficiency and durable SERS substrate.

Sensitive detection of monocrotophos using a voltametric immunosensor with randomly layered graphene oxide (GO) on fabricated electrode

Monocrotophos—a highly toxic organophosphate pesticide—is widely utilized in agriculture for managing crop-harming insects by inhibiting their acetylcholinesterase (AChE) enzyme. However, its excessive usage has led to acute poisoning incidents in animals and humans. Its high-water solubility resulted in significant leaching into the water bodies, causing pollution in those reservoirs. For addressing this concern and effective monitoring such contaminations, necessitated the development of a robust detection system. In response, we designed an electrochemical immunosensor (biosensor) primarily based on antibodies which specifically detects the monocrotophos. The initial step involved generating the biorecognition element, the anti-monocrotophos antibodies. This was achieved through the conjugation of monocrotophos to a carrier protein, bovine serum albumin (BSA) followed by immunization. Characterization of the resulting conjugate was carried out using spectroscopic, chromatographic, and electrophoretic methods. The antibodies were further analyzed by immunosorbent assays (ELISA) and SDS-PAGE to evaluate their properties. Subsequently, the generated antibodies were conjugated with graphene oxide (GO), acting as an electrochemical mediator, utilizing the zero-length conjugation method. The antibody-GO conjugate was then layered onto a fluorine-doped tin oxide (FTO) electrode for the electrochemical detection of monocrotophos by employing differential pulse voltammetry (DPV). The fabricated biosensor demonstrated a limit of detection (LOD) of 0.49 parts per million (ppm) and exhibited stability of up-to 4 weeks when stored. This developed system proves to be ideal for monitoring monocrotophos in laboratory settings and the first system to utilize the antibodies to specifically detect monocrotophos, presenting a promising approach to tackle its hazardous impact on the environment.

THE EFFECT OF SPIN COATING’S SPEED ON GRAPHENE-OXIDE’S LAYER TOPOGRAPHY AND QCM VISCOELASTICITY

Spin coating speed controls the deposition process, affecting the formation of the layer’s topography of graphene oxide and the viscoelastic properties of quartz crystal microbalance (QCM). In this work, the graphene oxide was deposited on the QCM surface by spin coating method with speeds ranging from 500 to 800 rpm. The layer’s surface topography was subsequently measured and analyzed using a roughness multiparameter, which included the area average (Sa), area roughness deviation (Sq), localized surface roughness (Sz), surface skewness (Ssk), and surface kurtosis (Sku). The Sa, Sq, and Sz, which were decreased as the spinning speed increased. The measurements indicated that the graphene oxide layer deposited at 500 rpm had a rough and clumpy texture, while at a high speed of 800 rpm, the layer had a much smoother texture. A detailed analysis using the Sku and Ssk parameters revealed that the clumpy texture in the 500 rpm sample contains tapered sharp graphene oxide structures and a small amount of porosity. On the other hand, the sharp structures were significantly reduced, and porosity was dominant in the sample deposited at high speeds of 700 rpm and 800 rpm. The effect of the spinning speed and the topography on the viscoelasticity was studied using an impedance analyzer. The impedance of the layer deposited at 500 rpm was relatively higher than that at 800 rpm. The frequency shift was also relatively significant for the sample deposited at low speed and was reduced at higher speed. The impedance analysis demonstrated that the layer’s viscosity is affected by its mass, roughness, texture, and porosity.

Quantifying defects in graphene oxide structures

Oxidation of graphite and subsequent exfoliation leads to single layer graphene oxide (GO). One of the key structural features of GO is the presence of different kinds of defects that dictates their various physical and chemical properties. Molecular dynamics simulations with ReaxFF force fields have been widely used to generate realistic models of GO. In these simulations, the extent and distribution of the defects are varied by changing the initial oxygen (O)/carbon (C) ratio while the defect density is often measured by the total number of non-graphitic carbon (non-gC) atoms. Our calculations suggest that this parameter overestimates the defect densities at low O/C ratio. Herein, we employ the relative area of the defects as an alternative metric to gauge the defect density. Being exclusive to the defects and sensitive to the structural irregularities, this metric works well at both low and high defect densities. In another example, we consider the reduction of GO to reduced graphene oxide (rGO) for different O/C ratios, where the decrease in the number of non-gC atoms is associated with the formation of comparatively larger defects. Hence, it is unclear whether the extent of reduction in the defect density (if at all) should vary monotonically with the O/C ratio. The defect area, unlike the count of the non-gC atoms, mirrors this ambiguity and the change with respect to O/C ratio is not strictly monotonic. Additionally, we also investigate the dependence of the defect distribution and defect area on the size of the simulation cell.

Electrophoretic deposition of graphene oxide as a stabilizing layer on the Ni-rich layered oxide electrodes for enhancing the cycling stability of Li-ion cathodes

One of the critical challenges for layered Ni-rich cathode material is the surface degradation caused by the parasitic reaction between the cathode material and the organic electrolytes. Herein, we develop an overall electrode modification strategy to improve the cathode surface's structural stability by integrating graphene oxide (GO) coating on the surface of the cathode electrode with the assistance of the electrophoretic deposition technique (EPD). The attenuated total reflectance (ATR) and scanning electron microscope (SEM) results confirm the formation of the uniform thin GO layer on the surface of the Ni-rich cathode. The electrochemical studies such as galvanostatic charge-discharge, galvanostatic intermittent titration Technique (GITT), and incremental capacity analysis (ICA) tests show that the existence of thin layers of GO not only does not hinder the intercalation of Li+ ions but also can facilitate the charge transfer and intercalation of Li+ ions by decreasing the charge transfer resistance of the electrode. The cycling stability of the cathode coated with GO in 30 s of EPD shows better performance over 150 charge-discharge cycles and lower Rct than the pristine electrode. Our work provides a design idea for stabilizing the surface/bulk structure of advanced Ni-rich cathode for high-performance Li-ion batteries.

Artificial ‘nacre-like’ architectures assembled using ice templating/freeze-drying from two-dimensional boron nitride and graphene oxide layers

Artificial ‘nacre-like’ architectures assembled using ice templating/freeze-drying from two-dimensional boron nitride and graphene oxide layers

The Development of New Nanoplatforms Based on Albumin and Graphene Oxide for Aticancer Therapy

This study focuses on the covalent functionalization of the carboxylated graphene oxide layers with human serum albumin for developing new nanoplatforms capable of efficient drug loading and release for antitumor therapy. Thus, new GO-HSA conjugates have been developed and their interactions with methotrexate (MTX) molecules were evidenced through FT-IR, UV-Vis and Raman spectroscopy. The cumulative in vitro release profiles of MTX drug from GO-HSA-MTX nanoplatforms were analyzed through UV-Vis spectroscopy showing a more controlled release behavior of MTX drug under acidic conditions that simulate the tumor microenvironment demonstrating the potential use of GO-HSA-MTX as antitumoral nanocarriers.

Ultra-compact and high-performance suspended aluminum scandium nitride Lamb wave humidity sensor with a graphene oxide layer.

The utilization of Microelectromechanical Systems (MEMS) technology holds great significance for developing compact and high-performance humidity sensors in human healthcare, and the Internet of Things. However, several drawbacks of the current MEMS humidity sensors limit their applications, including their long response time, low sensitivity, relatively large sensing area, and incompatibility with a complementary metal-oxide-semiconductor (CMOS) process. To address these problems, a suspended aluminum scandium nitride (AlScN) Lamb wave humidity sensor utilizing a graphene oxide (GO) layer is firstly designed and fabricated. The theoretical and experimental results both show that the AlScN Lamb wave humidity sensor exhibits high sensing performance. The mass loading sensitivity of the sensor is one order higher than that of the normal surface acoustic wave (SAW) humidity sensor based on an aluminum nitride (AlN) film; thus the AlScN Lamb wave humidity sensor achieves high sensitivity (∼41.2 ppm per % RH) with only an 80 nm-thick GO film. In particular, the as-prepared suspended AlScN Lamb wave sensors are able to respond to the wide relative humidity (0-80% RH) change in 2 s, and the device size is ultra-compact (260 μm × 72 μm). Moreover, the sensor has an excellent linear response in the 0-80% RH range, great repeatability and long-term stability. Therefore, this work brings opportunities for the development of ultra-compact and high-performance humidity sensors.