Bilayer Heterojunction Research Articles

In-Depth Study of Ambipolar Charge-Transport Regime through External Triggers and Gas Sensing.

Ambipolar devices are a hot topic in research tables due to their unique advantage in reducing the size of the electrical system and enhancing its efficiency. Here, we report a bilayer heterojunction device constructed using octafluoro-vanadyl-phthalocyanine (VOF8Pc) and lutetium bisphthalocyanine (LuPc2), which exhibits both p- and n-type behaviors under oxidizing (NO2 and O3) and reducing gas (NH3) species depending on the humidity level and temperature variations. The initial polarity of the device is identified as n-type by measuring a current decrease under oxygen exposure. Most interestingly, we were capable of observing the zero state (no response) where both opposite charge carriers fight for the majority to dominate the electrical properties of the device when it goes from n- to p-type or vice versa. The inversion in the nature of the majority charge carriers in this ambipolar device was achieved by optimizing the external trigger. The unique property of controllable polarity inversion in a VOF8Pc/LuPc2-based bilayer heterojunction device makes it the most effective ambipolar device for real-world applications.

Electronic and Optical Properties of 2D Heterostructure Bilayers of Graphene, Borophene and 2D Boron Carbides from First Principles.

In the present work the atomic, electronic and optical properties of two-dimensional graphene, borophene, and boron carbide heterojunction bilayer systems (Graphene-BC3, Graphene-Borophene and Graphene-B4C3) as well as their constituent monolayers are investigated on the basis of first-principles calculations using the HSE06 hybrid functional. Our calculations show that while borophene is metallic, both monolayer BC3 and B4C3 are indirect semiconductors, with band-gaps of 1.822 eV and 2.381 eV as obtained using HSE06. The Graphene-BC3 and Graphene-B4C3 bilayer heterojunction systems maintain the Dirac point-like character of graphene at the K-point with the opening of a very small gap (20-50 meV) and are essentially semi-metals, while Graphene-Borophene is metallic. All bilayer heterostructure systems possess absorbance in the visible region where the resonance frequency and resonance absorption peak intensity vary between structures. Remarkably, all heterojunctions support plasmons within the range 16.5-18.5 eV, while Graphene-B4C3 and Graphene-Borophene exhibit a π-type plasmon within the region 4-6 eV, with the latter possessing an additional plasmon at the lower energy of 1.5-3 eV. The dielectric tensor for Graphene-B4C3 exhibits complex off-diagonal elements due to the lower P3 space group symmetry indicating it has anisotropic dielectric properties and could exhibit optically active (chiral) effects. Our study shows that the two-dimensional heterostructures have desirable optical properties broadening the potential applications of the constituent monolayers.

A Surface-Reconstructed Bilayer Heterojunction Enables Efficient and Stable Inverted Perovskite Solar Cells.

The efficiency of perovskite photovoltaics remains distant from their theoretical limits, primarily due to high photovoltage losses. Here a strategy is reported to minimize voltage losses by reconstructing the perovskite surface into a bilayer heterojunction (BLH) structure. Unlike conventional low-dimensional capping layers, typically constrained to a few nanometers to prevent low fill factors, this methodology facilitates a more comprehensive reaction with surface defects, allowing a more substantial capping layer (≈50 nanometers) without compromising charge transport integrity. Time-resolved microwave conductivity analysis indicates a significant reduction in trap density at the top region of the perovskite film, showing an order of magnitude lower than that of the pristine sample. Incorporating this BLH in inverted cells results in a remarkably low photovoltage deficit of 325mV, leading to a power conversion efficiency (PCE) of 26.1% (25.72% certified). The encapsulated device maintains 94% of its original efficiency after 1200h of maximum power point tracking under one sun illumination at 65°C.

Optimizing Surface Characteristics of Stainless Steel (SUS) for Enhanced Adhesion in Heterojunction Bilayer SUS/Polyamide 66 Composites.

The increasing environmental concerns and stringent regulations targeting emissions and energy efficiency necessitate innovative material solutions that not only comply with these standards but also enhance performance and sustainability. This study investigates the potential of heterojunction bilayer composites comprising stainless steel (SUS) and polyamide 66 (PA66), aiming to improve fuel efficiency and reduce harmful emissions by achieving lightweight materials. Joining a polymer to SUS is challenging due to the differing physical and chemical properties of each material. To address this, various surface treatment techniques such as blasting, plasma, annealing, and etching were systematically studied to determine their effects on the microstructural, chemical, and mechanical properties of the SUS surface, thereby identifying mechanisms that improve adhesion. Chemical etching using HNO3/HCl and CuSO4/HCl increased surface roughness and mechanical properties, but these properties decreased after annealing. In contrast, K3Fe(CN)6/NaOH treatment increased the lap shear strength after annealing. Blasting increased surface roughness and toughness with increasing spray pressure and further enhanced these properties after annealing. Contact angle measurements indicated that the hydrophilicity of the SUS surface improved with surface treatment and further improved due to microstructure formation after annealing. This study demonstrates that customized surface treatments can significantly enhance the interfacial adhesion and mechanical properties of SUS/polymer heterojunction bilayer composites, and further research is recommended to explore the long-term stability and durability of these treatments under various environmental conditions.

Investigation of diodic behavior in p-NiO/n-SnO2 bilayer heterojunctions fabricated via DC magnetron reactive sputtering

Tin oxide (SnOx) thin films at varying oxygen flow rates and Nickel oxide (NiO) thin films were deposited by reactive dc magnetron sputtering on glass substrates. Structural, chemical, morphological, optical and electrical properties of the deposited films were studied. XRD studies confirmed that the deposited films were polycrystalline in nature. SnOx thin films have shown two phases such as SnO and SnO2. AFM and SEM were used to analyse the morphology of the films and EDS confirmed the presence of Sn and Ni in the respective films. The examination of the x-ray photoelectron spectrum showed that the sputtered SnOx films contain both Sn2+ and Sn4+ oxidation states and NiO films contain Ni+2 and Ni+3 oxidation states. Photoluminescence study shows strong violet and weak red emission peaks for SnOx films and NiO showed strong emission peaks in the orange-red region. The optical results demonstrate that the films were transparent. The bandgap of SnOx and NiO samples were ∼3.3 eV and − 3.42 eV, respectively. Further we constructed a p-NiO/n-SnO2 heterojunction diode and its electrical characteristics were thoroughly assessed. Using dark current–voltage measurements, electrical characteristics such saturation current, ideality factor and barrier height were determined. The increase in oxygen flow rate led to reduction in the rectification of the devices. Our findings support the creation of high-performance metal oxide heterojunction for optoelectronic devices.

Organic solar cells: Exploring the future and sustainability of clean energy

As a critical technology in renewable energy, organic solar cells play an important role in energy transition and sustainable development. This paper examines the development and significance of organic solar cells in terms of energy demand, environmental requirements, and industrial growth. With the development of China's energy structure adjustment and carbon peak carbon neutral targets, interest in novel energy technologies is growing. The paper then describes the interaction between photons and materials and the electron-hole separation and charge transport mechanism of organic solar cells. In addition, the characteristics and potential applications of organic solar cells with various structures, such as bilayer heterojunction devices, intrinsic heterojunction devices, molecular DA junction devices, and stacked devices, are described in depth. In the outlook section, the paper emphasizes the future potential of organic solar cells, including efficiency enhancements, cost reductions, and integration with energy storage technologies. In conclusion, organic solar cells have tremendous potential in the field of renewable energy, and they are anticipated to lead the energy transition and contribute to sustainable development.

A Palladium-Containing Polyoxotungstate with Anisotropic Proton Conductivity.

Here, a case of bilayer heterojunction Pd-containing polyoxotungstate (POW), connecting a Te3Pd3 ring and an Anderson-like TeW6 cluster, has been synthesized. The Anderson-like cluster is the first example in POW. The coordination of Pd in the ring with the S atom on the sulfo group breaks the traditional coordination configuration of Pd and O in polyoxometalates (POMs), enriching the structural types of Pd-containing POMs. In addition, the hybrid bilayer heterojunction structure at the molecular level not only provides high thermal stability but also results in spatial arrangement anisotropy, leading to up to five times the anisotropic proton conductivity.

Schottky barrier diode and photoelectric device based on two dimensional noble transition-metal sulfides vertical heterojunction

In this work, we use first-principles method to investigate the properties of two-dimensional noble transition-metal sulfides MS2 (M = Ni, Pd, Pt) and the electronic and optoelectronic applications of their vertical heterojunctions. The vertically bilayer or trilayer stacking can modulate the band structures and optical absorption spectra of MS2 (M = Ni, Pd, Pt) obviously. Therefore, we create the atomically thin Schottky barrier diodes (SBD) by vertically stacking the MS2 (M = Ni, Pd, Pt) on monolayer MS2 (M = Ni, Pd, Pt). All SBDs reveal more excellent current rectification behavior along the armchair edge (AE) transport direction than that along the zigzag edge (ZE) transport direction. SBD based on PdS2 bilayer and monolayer heterojunction has the high current value and the significant rectification ratio (exceeding 105) along AE transport direction. The total photocurrent densities of all SBDs along the ZE transport direction are bigger than that along the AE transport direction. SBD based on PdS2 bilayer and monolayer heterojunction has the largest total photocurrent density (1208.07 μA/mm2) along the ZE transport direction. Our work provides foundations for the application of two-dimensional noble transition-metal sulfides in rectification and optoelectronics.

Enhancing photoluminescence of WSe2 in vapor grown WSe2/VOCl bilayer heterojunctions via surface passivation.

Monolayer tungsten selenide (WSe2) has attracted attention due to its direct bandgap-generated strong light emission and light-matter interaction. Herein, vertical WSe2/VOCl bilayer heterojunctions with enhanced PL of WSe2 were synthesized by the vapor growth method. The morphology, crystal structure, and chemical composition of the WSe2/VOCl heterojunctions were systematically investigated, which confirmed the successful formation of the heterojunctions. The PL emission intensity of WSe2 obtained from the WSe2/VOCl heterojunction was about 2.4 times higher than that of the WSe2 monolayer, demonstrating the high optical quality of the WSe2/VOCl heterojunction, which was further confirmed by time-resolved PL measurements. The insulator top VOCl, which was deposited on the surface of the semiconductor bottom WSe2 as a surface passivation material, reducing the impurities and resulting in an atomically clean surface, successfully enhanced the PL emission of the bottom WSe2. This vertical WSe2/VOCl bilayer heterojunction with PL enhancement could provide a promising platform for optical devices.

Ambipolar Heterojunction Sensors: Another Way to Detect Polluting Gases.

Gas sensors based on ambipolar materials offer significant advantages in reducing the size of the analytical system and enhancing its efficiency. Here, bilayer heterojunction devices are constructed using different octafluorinated phthalocyanine complexes, with Zn and Co as metal centers, combined with a lutetium bisphthalocyanine complex (LuPc2). Stable p-type behavior is observed for the ZnF8Pc/LuPc2 device under both electron-donating (NH3) and -oxidizing (NO2 and O3) gaseous species, while the CoF8Pc/LuPc2 device exhibits n-type behavior under reducing gases and p-type behavior under oxidizing gases. The nature of majority of the charge carriers of Co-based devices varies depending on the nature of target gases, displaying an ambipolar behavior. Both heterojunction devices demonstrate stable and observable response toward all three toxic gases in the sub-ppm range. Remarkably, the Co-based device is highly sensitive toward ammonia with a limit of detection (LOD) of 200 ppb, whereas the Zn-based device demonstrates exceptional sensitivity toward oxidizing gases, with excellent LOD values of 4.9 and 0.75 ppb toward NO2 and O3, respectively, which makes it one of the most effective organic heterojunction sensors reported so far for oxidizing gases.

Simulation research of hole transport layer free CsPbI3/MAPbI3 heterojunction perovskite solar cells with an efficiency of 30.33 %

Constructing inorganic perovskite/organic-inorganic hybrid perovskite bilayer heterojunction perovskite solar cells (HPSC) could make far-reaching changes in solar cell power conversion efficiency (PCE). Herein, a carbon-based hole transport layer (HTL) free CsPbI3/MAPbI3 HPSC was designed and optimized by one-dimensional solar cell capacitance (SCAPS-1D) software. The film thickness, bulk defect density and doping concentration of each perovskite light absorption layer, and the interface defect density, the electrode work function and the operating temperature changes effect on the device performances were investigated. Under optimized conditions, the HPSC obtained the open circuit voltage (VOC) of 1.43 V, short circuit current density (JSC) of 23.39 mA cm−2, fill factor (FF) of 90.67 % and PCE of 30.33 %, which was much superior than the single junction perovskite solar cell due to the suited energy band structure.

Nonvolatile behavior of resistive switching memory in Ag/WOx/TiOy/ITO device based on WOx/TiOy heterojunction

Two-terminal structure memristors are the most promising electronic devices that could play a significant role in artificial intelligence applications of the next generation and the post-Moore era. In this work, we fabricated the memristive device by depositing a heterojunction WOx/TiOy functional layer onto an indium tin oxide substrate using magnetron sputtering. The Ag/WOx/TiOy/ITO device exhibits improved memory behavior of bipolar resistive switching (RS) nonvolatile compared to TiOy-based single-layer memristors, enabling it to meet high-density information storage requirements. Moreover, our device exhibited the coexistence of the negative differential resistance effect and the behavior of the RS memory. Through a comprehensive analysis of conductivity on the curve of current–voltage (I–V), a physical model based on the mechanism of space charge-limited current, ohmic conduction, and Schottky emission was suggested to explain the behavior device RS memory. This study's findings demonstrate that including a heterojunction bilayer WOx/TiOy as a functional layer can significantly improve the performance of memristive devices. This advancement expands the potential application of ferroelectric metallic oxide heterojunctions within the field of memristors.

The Role of Surface Treatment and Coupling Agents for Adhesion between Stainless Steel (SUS) and Polyamide (PA) of Heterojunction Bilayer Composites.

The growing demand for lightweight and durable materials in industries, such as the automotive, aerospace, and electronics industries, has spurred the development of heterojunction bilayer composites, combining the structural integrity of metals with the versatility of polymers. This study addresses the critical interface between stainless steel (SUS) and polyamide 66 (PA66), focusing on the pivotal role of surface treatments and various silane coupling agents in enhancing the adhesion strength of heterojunction SUS/PA66 bilayer composites. Through systematic surface modifications-highlighted by scanning electron microscopy, atomic force microscopy, and contact angle analyses-the study assessed the impact of increasing the surface area, roughness, and energy of SUS. X-ray photoelectron spectroscopy evaluations confirmed the strategic selection of specific silane coupling agents. Although some coupling agents barely influenced the mechanics, notably, aminopropyl triethoxysilane (A1S) and 3-glycidyl oxypropyl trimethoxysilane (ES) significantly enhanced the mechanical properties of the heterojunction bilayer composites, evidenced by the improved lap shear strength, elongation at break, and toughness. These advancements were attributed to the interfacial interactions at the metal-polymer interface. This research underscored the significance of targeted surface treatment and the judicious selection of coupling agents in optimizing the interfacial adhesion and overall performance of metal-polymer composites, offering valuable insights for the fabrication of materials where reduced weight and enhanced durability are paramount.

Modulating the majority charge carrier type and performance of organic heterojunction ammonia sensors by increasing peripheral fluorination of the silicon phthalocyanine sublayer

Silicon phthalocyanines (R2-SiPcs) are an emerging class of high-performance organic semiconductors which have recently found application in highly sensitive and selective bilayer organic heterojunction devices for ammonia (NH3) sensing. We report bilayer heterojunction devices based on axially-substituted bis(pentafluorophenoxy)silicon phthalocyanines of increasing peripheral fluorination ((F5PhO)2-FXSiPc) as a bottom layer and lutetium bis-phthalocyanine (LuPc2) and demonstrate how increased peripheral fluorination changes device operation from p-type to n-type in response to NH3. Sensors fabricated with (F5PhO)2-F16SiPc exhibits the smallest apparent energy barrier for interfacial charge transport by impedance spectroscopy due to better alignment of the semiconductor molecular orbitals with the semi-occupied molecular orbital of LuPc2. Bilayer heterojunction devices all demonstrated a limit of detection (LOD) below 1 ppm with (F5PhO)2-SiPc/LuPc2 yielding an LOD of 307 ppb and a sensitivity of −0.72%·ppm−1. Postdeposition thermal annealing of the (F5PhO)2-SiPc/LuPc2 device is shown to further enhance sensor performance with a 1.5-fold increase in sensitivity to −1.15%·ppm−1 and a LOD of 198 ppb.

Tuning of Interfacial Charge Transport in Organic Heterostructures via Aryl Electrografting for Efficient Gas Sensors.

Modulation of interfacial conductivity in organic heterostructures is a highly promising strategy to improve the performance of electronic devices. In this endeavor, the present work reports the fabrication of a bilayer heterojunction device, combining octafluoro copper phthalocyanine (CuF8Pc) and lutetium bis-phthalocyanine (LuPc2) and tunes the charge transport at the Cu(F8Pc)-(LuPc2) interface by aryl electrografting on the device electrode to improve the device NH3-sensing properties. Dimethoxybenzene (DMB) and tetrafluoro benzene (TFB) electrografted by an aryldiazonium electroreduction method form a few-nanometer-thick organic film on ITO. The conductivity of the heterojunction devices formed by coating a Cu(F8Pc)/LuPc2 bilayer over the aryl-grafted electrode strongly varies according to the electronic effects of the substituents in the aryl. Accordingly, DMB increases while TFB decreases the mobile charges accumulation at the Cu(F8Pc)-(LuPc2) interface. This is explained by the perfect alignment of the frontier molecular orbitals of DMB and Cu(F8Pc), facilitating charge injection into the Cu(F8Pc) layer. On the contrary, TFB behaves like a strong acceptor and reduces the mobile charges accumulation at the Cu(F8Pc)-(LuPc2) interface. Such interfacial conductivity variation influences the device NH3-sensing properties, which increase because of DMB grafting and decrease in the presence of TFB. DMB-based heterojunction devices contain four times higher active sites for NH3 adsorption and could detect NH3 down to 1 ppm with limited interference from humidity, making them suitable for real environment NH3 detection.

Nanostructured p-PbS/p-CuO sulfide/oxide bilayer heterojunction as a promising photoelectrode for hydrogen gas generation

Abstract Recently, the photoelectrochemical (PEC) water-splitting reaction for hydrogen (H2) production has been a competitive research route to realize clean and sustainable electric power. In this work, copper oxide (CuO) and PbS thin films were fabricated on commercial glass, respectively, using the techniques of successive ionic-layer adsorption and reaction and chemical bath deposition. These nanostructured thin films served successfully as photoelectrodes for the photogeneration of H2. In addition, a p-PbS/p-CuO bilayer system was also fabricated, and a remarkable boost in PEC efficiency was observed compared to pure CuO and PbS thin films. Optical examinations showed excellent absorbance properties of the p-PbS/p-CuO bilayer in the visible range, with a bandgap of ∼1.28 eV. X-ray diffraction analysis indicated a monoclinic CuO/cubic PbS crystalline structure with a particle size of ∼18 nm. The photocurrent density (J ph) values were obtained using a three-electrode electrochemical cell in 0.3 M Na2S2O3 electrolyte. The p-PbS/p-CuO photoelectrode demonstrated a J ph value of −0.390 mA cm−2, which is significantly higher than the values of −0.120 and −0.008 mA cm−2 for the pure PbS and CuO photoelectrodes, respectively. This improvement is attributed to the p-PbS/p-CuO oxide/sulfide bilayer heterojunction, which improved the visible light absorption and reduced the electron–hole (e–h) recombination. The effects of pH value, temperature light intensity, and wavelength were all additionally studied. Remarkably, the photoelectrodes were stable under a pH of ∼7, which makes them promising for H2 production using normal drinking/seawater. These findings confirm the ability of the prepared photoelectrodes to facilitate water splitting and H2 generation under various environmental, chemical, and illumination conditions.

ZnMn2O4/ZnMnO3/ZnO composite with novel bilayer heterojunction structure for enhanced lithium storage performance

Innovative anode materials with high capacity and good cyclic stability play a vital role on pursuing the high-performance lithium-ion batteries (LIBs). Herein, ZnMn2O4/ZnMnO3/ZnO composite with a unique bilayer heterojunction structure is successfully synthesized by sintering of ZIF-8 coated Zn1/3Mn2/3CO3. The crystal phase, microstructure and chemical composition of ZnMn2O4/ZnMnO3/ZnO composite are characterized to analyze the heterostructure in detail. When used as anode materials for LIBs, the rich heterostructure interface of the composite can adsorb more e- and Li+, improving the lithium storage behavior of material. Meanwhile, the build-in electric field generated by the heterojunction is conducive to accelerating the migration speed of e- and Li+, thus improving the conductivity of the material. As a result, after long-term cycles of 320 times, the specific capacity of ZnMn2O4/ZnMnO3/ZnO composite is up to 857.5 mAh g−1, and it still keeps a high specific capacity of 201.4 mAh g−1 at the high current of 5 C. These results indicate that ZnMn2O4/ZnMnO3/ZnO composite has great potential in the field of LIBs.

Effect of PTAA and PCBM concentrations on the electrical response of bilayer heterojunction PTAA/PCBM Diode

Poly[bis(4-phenyl) (2,4,6-trimethylphenylamine] (PTAA) is a new promising hole transport material, and [6,6]-Phenyl C61 butyric acid methyl ester (PCBM) is a suitable electron acceptor material. This study deposited thin-film PTAA and PCBM at different spin coatings ranging from 1000 rpm to 5000 rpm. Ultraviolet–visible (UV–vis) spectrometer, X-ray diffraction (XRD) machine, and scanning electron microscope (SEM) techniques were used to determine the optical properties and structural properties, respectively. Thermal annealing with temperatures of 80 °C, 100 °C, 120 °C, and 150 °C was introduced to improve the properties of the PTAA and PCBM thin film. The results of SEM images for PTAA annealed at 150 °C appeared to darken and melt, whereas PCBM annealed at 120 °C and 150 °C had granule properties. The ideality factors for bilayer heterojunction diodes and bulk heterojunction PTAA/PCBM diodes with increased layers were 5.8–60.2 and 30.8–77.2, respectively. The optimum spin rate for the bilayer heterojunction PTAA/PCBM was 5000 rpm. The most appropriate diode behavior of the bilayer was at 5.0/1.0 wt%, 1.0/5.0 wt%, and 3.0/3.0 wt% of PTAA/PCBM, with the calculated ideality factors of 5.8, 6.2, and 15.45 with turn-on voltage of 1.57 V, 1.70 V, and 1.82 V, respectively.

Ferromagnetic GdX (X = Cl, Br) Monolayers with Large Perpendicular Magnetic Anisotropy and High Curie Temperature

Two-dimensional (2D) ferromagnets with high Curie temperatures (TC) and large perpendicular magnetic anisotropy (PMA) are rare, but have great potential in the field of spintronics. The present work investigates the electronic and magnetic properties of GdX (X = Cl and Br) monolayers and the two layers of GdCl/GdBr heterojunctions by conducting in-depth theoretical calculations. As expected, both GdCl and GdBr monolayers are ferromagnetic and have large magnetic moments of ∼8 μB per Gd atom. Besides, they both show large PMA with magnetic anisotropy energies of 0.88 and 0.85 meV/unit cell and ultrahigh TC of 826 and 704 K, respectively. Significantly, they both have topological properties and spin-orbit-induced energy band reversion. In addition, we found two stable stacking configurations for the GdCl/GdBr bilayer heterojunction. The ultrahigh TC and topological properties are maintained in the two stacking configurations. Their easy magnetization axes shift from out-of-plane to in-plane directions as a result of the competition mainly between the Gd p and Gd d orbitals. These properties endow GdCl and GdBr monolayers with great potential for practical applications in the field of spintronic devices at the nanoscale.

Spatial-five coordination promotes the high efficiency of CoN4 moiety in graphene-based bilayer for oxygen reduction electrocatalysis: A density functional theory study

• The interlayer interfacial bonding of graphene-based bilayers improves the activity in oxygen reduction electrocatalysis. • The strong pd hybridization changes the Co ligand from the planar-four N 4 coordination into spatial-five N 4 + X coordination in bilayer heterojunctions. • The 4 e - - OOH associative mechanism is preferred over 2 e - - H 2 O 2 mechanism thermodynamically and kinetically. The searching of highly efficient catalysts for oxygen reduction reaction (ORR) has attracted particular attention. In this work, we construct the graphene-based bilayers BG/ X that consists by the CoN 4 embedded graphene as the upper layer and the X modified graphene as the bottom layer ( X = Si, P, S). The interfacial bonding between CoN 4 site and the X dopant is spontaneously formed due to the strong pd hybridization, which changes the Co ligand from the planar-four N 4 coordination into spatial-five N 4 + X one. The additive glue atom weakens too strong adsorptions of the ORR intermediates on CoN 4 site and thereby improves the ORR activities in comparison with the monolayer counterpart. From the free energy profiles, the overpotentials η are 0.47, 0.49 and 0.45 V for BG/Si a , BG/P a and BG/S a , respectively, being comparable to that of state-of-the-art Pt material. Besides, the kinetic barriers for the bilayers are less than 0.75 eV, an indicative of the room temperature activity. Furthermore, the combination of thermodynamic and kinetic analysis ensures the preference of 4 e - - OOH associative mechanism over 2 e - - H 2 O 2 mechanism, being beneficial for membrane stability against the H 2 O 2 corrosion. Therefore, the graphene-based bilayers deliver the high efficiencies for oxygen reduction electrocatalysis. Therefore, the interfacial bonding in the graphene-based bilayers provides an interesting strategy to suppress the poisoning phenomenon for the material design from atom scale.