Two-dimensional Black Phosphorus Research Articles

Surface Engineering of Two-Dimensional Black Phosphorus for Advanced Nanophotonics.

ConspectusEverything in the world has two sides. We should correctly understand its two sides to pursue the positive side and get rid of the negative side. Recently, two-dimensional (2D) black phosphorus (BP) has received a tremendous amount of attention and has been applied for broad applications in optoelectronics, transistors, logic devices, and biomedicines due to its intrinsic properties, e.g., thickness-dependent bandgap, high mobility, highly anisotropic charge transport, and excellent biodegradability and biocompatibility. On one hand, rapid degradation of 2D BP under ambient conditions becomes a vital bottleneck that largely hampers its practical applications in optical and optoelectronic devices and photocatalysis. On the other hand, just because of its ambient instability, 2D BP as a novel kind of nanomedicine in a cancer drug delivery system can not only satisfy effective cancer therapy but also enable its safe biodegradation in vivo. Until now, a variety of surface functionality types and approaches have been employed to rationally modify 2D BP to meet the growing requirements of advanced nanophotonics.In this Account, we describe our research on surface engineering of 2D BP in two opposite ways: (i) stabilizing 2D BP by various approaches for advanced nanophotonic devices with both remarkable photoresponse behavior and environmentally structural stability and (ii) making full use of biodegradation, biocompatibility, and biological activity (e.g., photothermal therapy, photodynamic therapy, and bioimaging) of 2D BP for the construction of high-performance delivery nanoplatforms for biophotonic applications. We highlight the targeted aims of the surface-engineered 2D BP for advanced nanophotonics, including photonic devices (optics, optoelectronics, and photocatalysis) and photoinduced cancer therapy, by means of various surface functionalities, such as heteroatom incorporation, polymer functionalization, coating, heterostructure design, etc. From the viewpoint of potential applications, the fundamental properties of surface-engineered 2D BP and recent advances in surface-engineered 2D BP-based nanophotonic devices are briefly discussed. For the photonic devices, surface-engineered 2D BP can not only effectively improve environmentally structural stability but also simultaneously maintain photoresponse performance, enabling 2D BP-based devices for a wide range of practical applications. In terms of the photoinduced cancer therapy, surface-engineered 2D BP is more appropriate for the treatment of cancer due to negligible toxicity and excellent biodegradation and biocompatibility. We also provide our perspectives on future opportunities and challenges in this important and fast-growing field. It is envisioned that this Account can attract more attention in this area and inspire more scientists in a variety of research communities to accelerate the development of 2D BP for more widespread high-performance nanophotonic applications.

Pd-intercalated black phosphorus: An efficient electrocatalyst for CO2 reduction.

Nanoconfined catalysts enhance stabilization of reaction intermediates, facilitate electron transfer, and safeguard active centers, leading to superior electrocatalytic activity, particularly in CO2 reduction reactions (CO2RR). Despite their effectiveness, crafting nanoconfined catalysts is challenging due to unclear formation mechanisms. In this study, we introduce an electrochemical method to grow Pd clusters within the interlayers of two-dimensional black phosphorus, creating Pd cluster-intercalated black phosphorus (Pd-i-BP) as an electrocatalyst. Using in situ electrochemical liquid phase transmission electron microscopy (EC-TEM), we revealed the synthesis mechanism of Pd-i-BP, involving electrochemically driven Pd ion intercalation followed by reduction within the BP layers. The Pd-i-BP electrocatalyst exhibits exemplary CO2-to-formate conversion, achieving 90% Faradaic efficiency for formate production, owing to its distinct nanoconfined structure that stabilizes intermediates and enhances electron transfer. Density functional theory (DFT) calculations underscore the structural benefits for enhancing intermediate adsorption and catalyzing the reaction. Our insights deepen understanding of nanoconfined material synthesis, promising advanced, high-efficiency catalysts.

Thermoelectric transport and Rashba spin splitting of black arsenic phosphorus under strain regulation

The Rashba spin-splitting and thermoelectric transport of two-dimensional black arsenic phosphorus (2D B-AsP) under strain control are studied using non-equilibrium Green's function and first-principles calculations. Firstly, we determine the stability range of 2D B-AsP under strain conditions, with biaxial strain ranging from −2% to +10% and uniaxial strain ranging from −9% to +10%. Secondly, we analyze the spin splitting at the point Γ under strain within the range from −1% to +2%, and find that the spin-splitting coefficient decreases with increasing strain. Thirdly, we discuss the effects of applying strain and changing temperature on 2D B-AsP thermoelectric transport. When the uniaxial compression strain is −4%, the ZT coefficient increases by 14.8%, and increases by 193.6% at a temperature of 600 K. Finally, when two external conditions exist simultaneously, the ZT coefficient of the material increases by 103.4%. The research results demonstrate the potential applications of 2D B-AsP in spintronics and thermoelectricity.

Electromechanical strain response of phosphorene nanotubes

Nanomaterials that undergo structural or other property changes upon application of external stimuli are called stimuli responsive materials and are particularly suited for drug delivery, biosensing or artificial muscle applications. Two-dimensional (2D) black phosphorus is an ideal material for such applications due to its remarkable electromechanical response. Given that one-dimensional (1D) black phosphorus nanotubes (PNTs) are calculated to be energetically stable, it is possible that they can undergo similar electromechanical responses to their 2D counterparts, allowing their potential application as nanochannel devices for drug delivery. Using first-principles density functional theory, we investigated the electromechanical response of different-sized PNTs upon charge injection. Upon hole injection, the diameter of the PNTs expands up to a maximum of 30.2% for a (0,15) PNT that is 0.24 nm in diameter. The PNTs become highly p-doped as the valence band maximum crosses the Fermi level and undergoes switching from a direct to indirect band gap. The mechanism behind the electromechanical response was determined through analysis of the structural deformations, charge density distribution and Bader partial charges. It was shown that injection of charge alters the Young’s Modulus of the PNTs, as hole injection weakens the structural integrity of the nanotube, allowing a greater electromechanical response, with PNT-15 showing the largest decrease in the Young’s Modulus of 15.34%. These findings show that 1D PNTs are promising materials for the development of nanoelectromechanical actuators which could be used for drug delivery, energy harvesting or similar applications.

Nanoscale Evaluation of the Degradation Stability of Black Phosphorus Nanosheets Functionalized with PEG and Glutathione-Stabilized Doxorubicin Drug-Loaded Gold Nanoparticles in Real Functionalized System.

Two-dimensional black phosphorus (2D BP) has attracted significant research interest in the field of biomedical applications due to its unique characteristics, including high biocompatibility, impressive drug-loading efficiency, phototherapeutic ability, and minimal side effects. However, its puckered honeycomb lattice structure with lone-pair electrons of BP leads to higher sensitivity and chemical reactivity towards H2O and O2 molecules, resulting in the degradation of the structure with physical and chemical changes. In our study, we synthesize polyethylene glycol (PEG) and glutathione-stabilized doxorubicin drug-assembled Au nanoparticle (Au-GSH-DOX)-functionalized BP nanosheets (BP-PEG@Au-GSH-DOX) with improved degradation stability, biocompatibility, and tumor-targeting ability. Transmission electron microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy indicate the nanoscale degradation behavior of synthesized nanoconjugates in three different environmental exposure conditions, and the results demonstrate the remarkable nanoscale stability of BP-PEG@Au-GSH-DOX against the degradation of BP, which provides significant interest in employing 2D BP-based nanotherapeutic agents for tumor-targeted cancer phototherapy.

Controllable preparation of black phosphorus nanomaterials via liquid-phase pulsed discharge

The N, N-dimethylformamide (DMF) organic solvent was deliberately chosen as the optimal medium for this investigation. To achieve uniform dispersion of black phosphorus powder, which was obtained via shock-induced phase transformation, it was effectively dispersed in the DMF solution, resulting in a homogeneous black phosphorus-DMF suspension. Subsequently, a liquid-phase pulsed discharge experiment was conducted. This experimental setup harnessed the shockwave and tensile stripping effects generated by the rapid expansion of plasma during the liquid-phase pulsed discharge. These phenomena facilitated the interlayer exfoliation and dispersion of black phosphorus molecules, ultimately leading to the formation of a suspension containing black phosphorus quantum dots. In-depth investigation into the formation mechanism of black phosphorus quantum dots was also undertaken. Our findings reveal a pivotal influence of the charging voltage on the microstructure of the recovered samples. Specifically, as the charging voltage increases, the lateral dimensions of the retrieved two-dimensional black phosphorus powder undergo a remarkable reduction, transitioning from the micron-scale to less than 10 nm. The above results, which stem from meticulous experimentation and analysis, emphasize the significance of controlled synthesis in producing black phosphorus quantum dots with varying microstructures. Such insights hold substantial promise for advancing the field of materials science and enhancing the applicability of black phosphorus quantum dots in diverse applications.

Unified understanding to the rich electronic-structure evolutions of two-dimensional black phosphorus under pressure

Unified understanding to the rich electronic-structure evolutions of two-dimensional black phosphorus under pressure

Supramolecular elastomers with high strength and low toxicity are suitable for safety protection

Elastomer with high strength and toughness, temperature resistance and low smoke toxicity have shown great application prospects in the field of safety protection. In order to meet the needs of high strength, high toughness and smoke toxicity safety, a high-strength structural elastomer is formed by introducing the integration of hard skeleton and soft elastomer, that is, two-dimensional black phosphorus with high flame retardant efficiency and bimetallic hydroxide with catalytic detoxification (BP-MA-LDH) as the hard skeleton, based on the special combination of internal hydrogen bonds. High strength supramolecular poly(Urethane) (SPU) elastomer was manufactured by molecular design. The high strength and toughness SPU elastomer also has a tensile strength of 53.77 Ma and a elongation at break of 715.26 %. The addition of 2.0 wt% BP-MA-LDH reduces the heat release rate of SPU by 58.84 % and the smoke production release by 61.54 %. In terms of flue gas toxicity inhibition, Fractional Effective Dose was used to evaluate the flue gas toxicity of elastomer composites, and the release of CO, HCN, oxynitride and other toxic gases were greatly reduced. The synthetic performance of SPU elastomer composites in strengthening and toughening, smoke suppression and toxicity reduction is much better than that reported by peers.

Flexible and Ultra Low Weight Energy Harvesters Based on 2D Phosphorene or Black phosphorus (BP): Current and Futuristic Prospects.

Phosphorene, or two-dimensional (2D) black phosphorus, has recently emerged as a competitor of graphene as it offers several advantages, including a tunable band gap, higher on/off current ratio, piezoelectric nature, and biocompatibility. Researchers have succeeded in obtaining several forms of phosphorene, such as nanosheets, nanorods, nanoribbons, and quantum dots, with satisfactory yields. Nanostructures with various controlled properties have been fabricated in multiple devices for energy production. These phosphorene-based devices are lightweight, flexible, and efficient, demonstrating great potential for energy-harvesting applications in sensors and nanogenerators. While ongoing exploration and advancements continue for these lightweight energy harvesters, it is essential to review the current progress in order to develop a future roadmap for the potential use of these phosphorene-based energy harvesters in space programs. They could be employed in applications such as wearable devices for astronauts, where ultralow weight is a vital component of any integrated device. This review also anticipates the growing significance of phosphorene in various emerging applications such as robots, information storage devices, and artificial intelligence.

Incorporation of black phosphorus nanosheets into poly(propylene fumarate) biodegradable bone cement to enhance bioactivity and osteogenesis

BackgroundInjectable bone cement is commonly used in clinical orthopaedics to fill bone defects, treat vertebral compression fractures, and fix joint prostheses during joint replacement surgery. Poly(propylene fumarate) (PPF) has been proposed as a biodegradable and injectable alternative to polymethylmethacrylate (PMMA) bone cement. Recently, there has been considerable interest in two-dimensional (2D) black phosphorus nanomaterials (BPNSs) in the biomedical field due to their excellent photothermal and osteogenic properties. In this study, we investigated the biological and physicochemical qualities of BPNSs mixed with PPF bone cement created through thermal cross-linking.MethodsPPF was prepared through a two-step process, and BPNSs were prepared via a liquid phase stripping method. BP/PPF was subsequently prepared through thermal cross-linking, and its characteristics were thoroughly analysed. The mechanical properties, cytocompatibility, osteogenic performance, degradation performance, photothermal performance, and in vivo toxicity of BP/PPF were evaluated.ResultsBP/PPF exhibited low cytotoxicity levels and mechanical properties similar to that of bone, whereas the inclusion of BPNSs promoted preosteoblast adherence, proliferation, and differentiation on the surface of the bone cement. Furthermore, 200 BP/PPF demonstrated superior cytocompatibility and osteogenic effects, leading to the degradation of PPF bone cement and enabling it to possess photothermal properties. When exposed to an 808-nm laser, the temperature of the bone cement increased to 45–55 °C. Furthermore, haematoxylin and eosin-stained sections from the in vivo toxicity test did not display any anomalous tissue changes.ConclusionBP/PPF exhibited mechanical properties similar to that of bone: outstanding photothermal properties, cytocompatibility, and osteoinductivity. BP/PPF serves as an effective degradable bone cement and holds great potential in the field of bone regeneration.

Two-Dimensional Biodegradable Black Phosphorus Nanosheets Promote Large Full-Thickness Wound Healing through In Situ Regeneration Therapy.

Large full-thickness skin lesions have been one of the most challenging clinical problems in plastic surgery repair and reconstruction. To achieve in situ skin regeneration and perfect clinical outcomes, we must address two significant obstacles: angiogenesis deficiency and inflammatory dysfunction. Recently, black phosphorus has shown great promise in wound healing. However, few studies have explored the bio-effects of BP to promote in situ skin regeneration based on its nanoproperties. Here, to investigate whether black phosphorus nanosheets have positive bio-effects on in situ skin repair, we verified black phosphorus nanosheets' positive effects on angiogenic and anti-inflammatory abilities in vitro. Next, the in vivo evaluation performed on the rat large full-thickness excisional wound splinting model more comprehensively showed that the positive bio-effects of black phosphorus nanosheets are multilevel in wound healing, which can effectively enhance anti-inflammatory ability, angiogenesis, collagen deposition, and skin re-epithelialization. Then, multiomics analysis was performed to explore further the mechanism of black phosphorus nanosheets' regulation of endothelial cells in depth. Molecular mechanistically, black phosphorus nanosheets activated the JAK-STAT-OAS signaling pathway to promote cellular function and mitochondrial energy metabolism in endothelial cells. This study can provide a theoretical basis for applying two-dimensional black phosphorus nanosheets as nanomedicine to achieve in situ tissue regeneration in complex human pathological microenvironments, guiding the subsequent optimization of black phosphorus.

Transition metal induced- magnetization and spin-polarisation in black arsenic phosphorous

The electronic and magnetic properties of two-dimensional black Arsenic Phosphorus (b-AsP) on adsorption of Transition Metals (TM) on its surface are investigated using density functional theory (DFT) based on first principles calculations. Spin-density of states (S-DOS) and the bandstructure of all the transition metals adsorbed structures have been plotted which reveals their change from non-magnetic to magnetic behaviour. The results suggest that pristine b-AsP which is a non-magnetic semiconductor turns into a half metal ferromagnet (HMF) on adsorption of Co, Fe and Ti, and it turns into a ferromagnet (FM) on adsorption of Cr and Zr. The total magnetic moments were also calculated to further support our results and findings. Strong magnetic moments were observed for Cr, Fe and Ti adsorbed b-AsP structures. Ag, Cu and Mo adsorption over b-AsP results into non-magnetic metallic characteristics with very weak magnetic moments. This transformation from a non-magnetic semiconductor to a magnetic HMF or FM material demonstrates the potential use of b-AsP in designing spin magnetic devices for various spin-based applications.

Atomic-scale evolution of hydrogenated fullerene-like carbon in the presence of black phosphorus

Hydrogenated diamond-like carbon (H-DLC) is widely used by the industry, but over the past few decades, its mechanical properties have been hindered by oxidation stemming from frictional contact and heat generation. Herein, we propose a solution by establishing a tribosystem that incorporates two-dimensional black phosphorus (BP) nanosheets and H-DLC. Experiments and atomistic simulations reveal that integration of BP nanosheets to the sliding interface not only shields H-DLC from oxygen erosion, but also creates reactive sites for the formation of hydrogenated fullerene-like carbon (FLC:H) via covalent and hydrogen bonding interactions, resulting in significantly reduced friction. These findings provide a novel insight into the atomic-scale evolution of FLC:H and reveal promising prospects for expanding the industrial application of hydrogenated carbon films.

Application of two-dimensional black phosphorus material in wound healing

Abstract The efficient healing of skin wounds and tissue wounds has been the focus of clinical research. The complex process of body wound healing and various influencing factors make it more important to construct multifunctional composite wound tissue engineering materials that can meet all requirements. Black phosphorus (BP) is a multifunctional two-dimensional material with good biocompatibility, oxidative stress regulation ability, photothermal effect, and antibacterial ability. It has been widely used in biomedical engineering. In this review, the pathophysiological process and influencing factors of wound healing will be briefly introduced. On this basis, the properties, preparation methods, application status, and mechanism of action of BP in wound tissue engineering will be introduced in detail. This study will provide a reference for the further application of BP in wound tissue engineering materials by subsequent researchers.

Structural engineering of two-dimensional black phosphorus towards advanced photonic integrated circuits

Structural engineering is crucial for tuning the properties of artificial materials. As one of the most important two-dimensional (2D) materials, black phosphorus (BP) has been rediscovered in 2014 and attracted tremendous attentions all over the world. It shows great potentials in optoelectronic and integrated photonic applications due to the direct and tunable bandgap, high carrier mobility, and intrinsic anisotropy. However, some deficiencies are yet to be settled before its large-scale applications, such as the massive synthesis methods and structure–property relationship. To investigate the influence of structural engineering on the performance of 2D BP-based devices thoroughly, recent studies on deformation, atomic defects, superlattice, alloying, thickness and phase transition are maximality summarized in this review covering from the intrinsic properties to optoelectronic applications. Benefiting from the broad research in this field, challenges and opportunities of 2D BP for advanced integrated photonic applications are also provided, which supplies a useful reference to realize large-scale 2D BP-based all-optical communications in future.

Reducing charge-recombination losses in photovoltaic cells by spontaneous reconstruction of n/p homojunction in a monolithic perovskite film using black phosphorus nanosheets

Trap-assisted charge recombination and interfacial charge recombination have limited further improvements in the efficiency and stability of perovskite solar cells. We construct a novel two-dimensional (2D) black phosphorus nanosheet (BP NS)-modified perovskite model that utilizes an upgraded additive post-processing technique to introduce 2D BP NSs, comprising multiple functional groups and carrying a high charge mobility and high work function, into the absorber during Ostwald ripening. 2D BP NSs, while passivating grain boundaries and surface defects, successfully induced the in-situ formation of an intriguing n/p homojunction structure between the underlying bulk and the top in a monolithic perovskite film, i.e., a graded n/p-PVK-BP absorber. This resulted in the synergistic advantages of expanding the built-in electric field to facilitate the oriented transfer of photogenerated carriers, optimizing the energy level alignment, and minimizing the hole injection barrier at the perovskite/hole transporting layer interface, thereby accelerating the selective extraction/collection of interfacial charges and synchronously reducing nonradiative and interfacial charge recombination losses. The 2D BP NSs anchored at the grain boundaries and surface of p-type perovskite form a “fast path” for hole migration, achieving carrier transport balance at the top and bottom interfaces. The optimized n/p-PVK-BP device achieved an efficiency of 23.22 %, with negligible hysteresis. Owing to the synergistic effects of the various advantages of the graded n/p-PVK-BP homojunction absorber, the unencapsulated device exhibited good long-term storage and operational stability, providing potential for commercial conversion of perovskite-based optoelectronics. This work provides a simple homojunction structure design and performance optimization strategy for the simultaneous reduction of trap-assisted charge recombination and interfacial charge recombination losses and provides new insights for the development of more efficient and stable perovskite photovoltaic applications.

Synthesis of Black Phosphorene/P-Rich Transition Metal Phosphide NiP3 Heterostructure and Its Effect on the Stabilization of Black Phosphorene

Black phosphorus (BP), as a direct band gap semiconductor material with a two-dimensional layered structure, has a good application potential in many aspects, but the surface state of it is extremely unstable, especially that of single-layer black phosphorus. In this study, BP crystals and two-dimensional black phosphorus (2D BP) are prepared by a mechanical ball-milling–liquid-phase exfoliation method. The X-ray diffraction (XRD) spectrum and high-resolution transmission electron microscopy (HRTEM) results showed that red phosphorus (RP) successfully turned to BP by the mechanical ball-milling method. The spectrophotometric analysis has detected absorption peaks at 780 nm, 915 nm, and 1016 nm, corresponding to single, double, and three-layer BP bandgap emission. A simple solvothermal strategy is designed to synthesize in-plane BP/P-rich transition metal phosphide (TMP) heterostructures (BP/NiP3) by defect/edge-selective growth of NiP3 on the BP nanosheets. HRTEM analysis indicates that the metal ions are preferentially deposited on the defects of 2D BP such as edges and unsaturated sites, forming a 2D BP/NiP3 in-plane heterojunction.

Black Phosphorus-Based ZnO-Ag Nanocomposite for Antibacterial Activity against Tigecycline-Resistant Acinetobacter baumannii

Acinetobacter baumannii is a critically hard-to-treat gram-negative pathogen responsible for a range of infectious diseases. Tigecycline is a last-resort antibiotic for A. baumannii infection; however, tigecycline-resistant (TIG-R) A. baumannii has been increasingly reported. Therefore, new strategies must be developed to treat these detrimental infections. Nanoantibiotics composed of two-dimensional (2D) black phosphorus (BP) and its derived nanocomposites have emerged as excellent alternatives to current antibiotics. However, the development of unique materials to target specific pathogens is challenging. Here, we report the preparation of a BP-based ZnO-Ag (ZPBA) nanocomposite. A low-temperature solution synthesis method was used to prepare ZnO and Ag nanoparticles immobilized on BP nanosheets. X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy were used to characterize the ZPBA nanocomposite. The antibacterial activity of ZPBA nanocomposite was assessed by determining its minimum inhibitory concentration against type (ATCC 19606, ATCC 15150) and TIG-R (ATCC 19606-R) A. baumannii strains. From the assays, ZPBA showed superior activity against TIG-R A. baumannii strain with MIC of 12.5 µg·mL−1 compared to all other prepared samples. Finally, the combination of bacterial membrane disruption and ROS generation was demonstrated to be a potential antibacterial mechanism of ZPBA. Our results show that ZPBA could be a potential nanoantibiotic platform for eradicating TIG-R A. baumannii.

HER2-targeting two-dimensional black phosphorus as a nanoplatform for chemo-photothermal therapy in breast cancer

Trastuzumab (Tmab) targeted therapy or its combination with chemotherapy is normally insufficient to elicit a comprehensive therapeutic response owing to the inherent or acquired drug resistance and systemic toxicity observed in highly invasive HER2-positive breast cancer. In this study, we propose a novel approach that integrates photothermal therapy (PTT) with targeted therapy and chemotherapy, thereby achieving additive or synergistic therapeutic outcomes. We utilize PEGylated two-dimensional black phosphorus (2D BP) as a nanoplatform and photothermal agent to load chemotherapeutic drug mitoxantrone (MTO) and conjugate with Tmab (BP-PEG-MTO-Tmab). The in vitro and in vivo experiments demonstrated that the HER2-targeting BP-PEG-MTO-Tmab complexes exhibited desirable biocompatibility, safety and enhanced cancer cell uptake efficiency, resulting in increased accumulation and prolonged retention of BP and MTO within tumors. Consequently, the complex improved photothermal and chemotherapy treatment efficacy in HER2-positive cells in vitro and a subcutaneous tumor model in vivo, while minimized harm to normal cells and showed desirable organ compatibility. Collectively, our study provides compelling evidence for the remarkable efficacy of targeted and synergistic chemo-photothermal therapy utilizing all-in-one nanoparticles as a delivery system for BP and chemotherapeutic drug in HER2-positive breast cancer.

Black Phosphorus Field-Effect Transistors with Improved Contact via Localized Joule Heating.

Two-dimensional (2D) black phosphorus (BP) is considered an ideal building block for field-effect transistors (FETs) owing to its unique structure and intriguing properties. To achieve high-performance BP-FETs, it is essential to establish a reliable and low-resistance contact between the BP and the electrodes. In this study, we employed a localized Joule heating method to improve the contact between the 2D BP and gold electrodes, resulting in enhanced BP-FET performance. Upon applying a sufficiently large source-drain voltage, the zero-bias conductance of the device increased by approximately five orders of magnitude, and the linearity of the current-voltage curves was also enhanced. This contact improvement can be attributed to the formation of gold phosphide at the interface of the BP and the gold electrodes owing to current-generated localized Joule heat. The fabricated BP-FET demonstrated a high on/off ratio of 4850 and an on-state conductance per unit channel width of 1.25 μS μm-1, significantly surpassing those of the BP-FETs without electrical annealing. These findings offer a method to achieve a low-resistance BP/metal contact for developing high-performance BP-based electronic devices.