With the advantage of fast charge transfer,heterojunction engineering is identified as a viable method to reinforce the anodes'sodium storage performance.Also,vacancies can effectively strengthen the Na+adsorption...With the advantage of fast charge transfer,heterojunction engineering is identified as a viable method to reinforce the anodes'sodium storage performance.Also,vacancies can effectively strengthen the Na+adsorption ability and provide extra active sites for Na+adsorption.However,their synchronous engineering is rarely reported.Herein,a hybrid of Co_(0.85)Se/WSe_(2) heterostructure with Se vacancies and N-doped carbon polyhedron(CoWSe/NCP)has been fabricated for the first time via a hydrothermal and subsequent selenization strategy.Spherical aberration-corrected transmission electron microscopy confirms the phase interface of the Co_(0.85)Se/WSe_(2) heterostructure and the existence of Se vacancies.Density functional theory simulations reveal the accelerated charge transfer and enhanced Na+adsorption ability,which are contributed by the Co_(0.85)Se/WSe_(2) heterostructure and Se vacancies,respectively.As expected,the CoWSe/NCP anode in sodium-ion battery achieves outstanding rate capability(339.6 mAh g^(−1) at 20 A g^(−1)),outperforming almost all Co/W-based selenides.展开更多
Graphene, with its zero-bandgap electronic structure, is a highly promising ultra-broadband light absorbing material.However, the performance of graphene-based photodetectors is limited by weak absorption efficiency a...Graphene, with its zero-bandgap electronic structure, is a highly promising ultra-broadband light absorbing material.However, the performance of graphene-based photodetectors is limited by weak absorption efficiency and rapid recombination of photoexcited carriers, leading to poor photodetection performance. Here, inspired by the photogating effect, we demonstrated a highly sensitive photodetector based on graphene/WSe_(2) vertical heterostructure where the WSe_(2) layer acts as both the light absorption layer and the localized grating layer. The graphene conductive channel is induced to produce more carriers by capacitive coupling. Due to the strong light absorption and high external quantum efficiency of multilayer WSe_(2), as well as the high carrier mobility of graphene, a high photocurrent is generated in the vertical heterostructure. As a result, the photodetector exhibits ultra-high responsivity of 3.85×10~4A/W and external quantum efficiency of 1.3 × 10~7%.This finding demonstrates that photogating structures can effectively enhance the sensitivity of graphene-based photodetectors and may have great potential applications in future optoelectronic devices.展开更多
Two-dimensional(2D)WSe_(2)has received increasing attention due to its unique optical properties and bipolar behavior.Several WSe_(2)-based heterojunctions exhibit bidirectional rectification characteristics,but most ...Two-dimensional(2D)WSe_(2)has received increasing attention due to its unique optical properties and bipolar behavior.Several WSe_(2)-based heterojunctions exhibit bidirectional rectification characteristics,but most devices have a lower rectification ratio.In this work,the Bi_(2)O_(2)Se/WSe_(2)heterojunction prepared by us has a typeⅡband alignment,which can vastly suppress the channel current through the interface barrier so that the Bi_(2)O_(2)Se/WSe_(2)heterojunction device has a large rectification ratio of about 10^(5).Meanwhile,under different gate voltage modulation,the current on/off ratio of the device changes by nearly five orders of magnitude,and the maximum current on/off ratio is expected to be achieved 106.The photocurrent measurement reveals the behavior of recombination and space charge confinement,further verifying the bidirectional rectification behavior of heterojunctions,and it also exhibits excellent performance in light response.In the future,Bi_(2)O_(2)Se/WSe_(2)heterojunction field-effect transistors have great potential to reduce the volume of integrated circuits as a bidirectional controlled switching device.展开更多
Green hydrogen is urgently required for sustainable development of human beings and rational construction of heterostructures holds great promising for photocatalytic hydrogen generation.Herein,2D/2D WSe_(2)/ZnIn_(2)S...Green hydrogen is urgently required for sustainable development of human beings and rational construction of heterostructures holds great promising for photocatalytic hydrogen generation.Herein,2D/2D WSe_(2)/ZnIn_(2)S_(4) heterostructures with strong hetero-interface interaction and abundant contact were constructed via an impregnation-annealing strategy.Efficient charge transfer from ZnIn_(2)S_(4) to WSe_(2)was evidenced by transient absorption spectroscopy in crafted heterostructures owing to the tight and2D face-to-face contact.As a result,the prepared WSe_(2)/ZnIn_(2)S_(4) heterostructures exhibited boosted photocatalytic performance and a highest hydrogen evolution rate of 3.377 mmol/(g h)was achieved with an apparent quantum yield of 45.7%at 420 nm.The work not only provides new strategies to achieve efficient 2D/2D heterostructures but also paves the way for the development of green hydrogen in the future.展开更多
Polarization-resolved photodetectors,a significant branch of photodetection,can more effectively distinguish the target from the background by exploiting polarization-sensitive characteristics.However,due to the absen...Polarization-resolved photodetectors,a significant branch of photodetection,can more effectively distinguish the target from the background by exploiting polarization-sensitive characteristics.However,due to the absence of intrinsic polarized absorption properties of many materials,there is still a great challenge to develop the high-performance polarization-resolved photodetectors.Here,we report a van der Waals heterojunction(vdWH)ReSe_(2)/WSe_(2)photodetector,which performs a high responsivity of~0.28 A/W and a high detectivity of 1.1×10^(12)Jones under the illumination of 520 nm laser at room temperature.Remarkably,scanning photocurrent mapping(SPCM)measurements demonstrate the photoresponse of devices closely depend on the polarized angle of the incident light,indicating the effective polarized light detection.This work paves the way to develop high-performance polarization-resolved photodetectors based on two-dimensional(2D)materials.展开更多
过渡金属硫化物(transition metal dichalcogenides,TMDs)具有优异的光学、电学性能,其中,二维WSe_(2)薄膜作为典型的TMDs类材料之一,凭借其可调控的光学带隙,在光电子器件领域有极大的潜在应用价值。但是,由于单层的WSe_(2)薄膜具有较...过渡金属硫化物(transition metal dichalcogenides,TMDs)具有优异的光学、电学性能,其中,二维WSe_(2)薄膜作为典型的TMDs类材料之一,凭借其可调控的光学带隙,在光电子器件领域有极大的潜在应用价值。但是,由于单层的WSe_(2)薄膜具有较低的光学吸收截面,对于光的吸收效率较弱,限制了其在光电器件中的应用发展。因此,如何提高单层WSe_(2)薄膜的光吸收和光发射效率成为了人们的研究热点。本文将单层WSe_(2)薄膜作为研究对象构建了Au膜-WSe_(2)复合结构,通过显微光致发光光谱分析其光学性能,分别对比了Au膜-WSe_(2)交界处和Au膜-WSe_(2)复合区域与纯WSe_(2)区域的发光特性,研究表明Au膜与WSe_(2)薄膜直接接触发生了荧光淬灭效应,发光强度减弱;而在两者交界处,受到金属表面等离极化激元效应的作用,交界处的发光强度有明显的增强;为了解释这现象,本文建立了相应的物理模型来解释Au膜-WSe_(2)复合结构的发光特性。展开更多
基金support from the Natural Science Foundation of Jilin Province(Grant No.20200201073JC)the National Natural Science Foundation of China(Grant No.52130101)+1 种基金Interdisciplinary Integration and Innovation Project of JLU(Grant No.JLUXKJC2021ZY01)the Fundamental Research Funds for the Central Universities.
文摘With the advantage of fast charge transfer,heterojunction engineering is identified as a viable method to reinforce the anodes'sodium storage performance.Also,vacancies can effectively strengthen the Na+adsorption ability and provide extra active sites for Na+adsorption.However,their synchronous engineering is rarely reported.Herein,a hybrid of Co_(0.85)Se/WSe_(2) heterostructure with Se vacancies and N-doped carbon polyhedron(CoWSe/NCP)has been fabricated for the first time via a hydrothermal and subsequent selenization strategy.Spherical aberration-corrected transmission electron microscopy confirms the phase interface of the Co_(0.85)Se/WSe_(2) heterostructure and the existence of Se vacancies.Density functional theory simulations reveal the accelerated charge transfer and enhanced Na+adsorption ability,which are contributed by the Co_(0.85)Se/WSe_(2) heterostructure and Se vacancies,respectively.As expected,the CoWSe/NCP anode in sodium-ion battery achieves outstanding rate capability(339.6 mAh g^(−1) at 20 A g^(−1)),outperforming almost all Co/W-based selenides.
基金Project supported by the National Natural Science Foundation of China (Grant No.11974379)the National Key Basic Research and Development Program of China (Grant No.2021YFC2203400)Jiangsu Vocational Education Integrated Circuit Technology “Double-Qualified” Famous Teacher Studio (Grant No.2022-13)。
文摘Graphene, with its zero-bandgap electronic structure, is a highly promising ultra-broadband light absorbing material.However, the performance of graphene-based photodetectors is limited by weak absorption efficiency and rapid recombination of photoexcited carriers, leading to poor photodetection performance. Here, inspired by the photogating effect, we demonstrated a highly sensitive photodetector based on graphene/WSe_(2) vertical heterostructure where the WSe_(2) layer acts as both the light absorption layer and the localized grating layer. The graphene conductive channel is induced to produce more carriers by capacitive coupling. Due to the strong light absorption and high external quantum efficiency of multilayer WSe_(2), as well as the high carrier mobility of graphene, a high photocurrent is generated in the vertical heterostructure. As a result, the photodetector exhibits ultra-high responsivity of 3.85×10~4A/W and external quantum efficiency of 1.3 × 10~7%.This finding demonstrates that photogating structures can effectively enhance the sensitivity of graphene-based photodetectors and may have great potential applications in future optoelectronic devices.
基金This work was supported by the National Natural Science Foundation of China(61704054,92161115,62374099,and 62022047)the Fundamental Research Funds for the Central Universities(JB2020MS042 and JB2019MS051).
文摘Two-dimensional(2D)WSe_(2)has received increasing attention due to its unique optical properties and bipolar behavior.Several WSe_(2)-based heterojunctions exhibit bidirectional rectification characteristics,but most devices have a lower rectification ratio.In this work,the Bi_(2)O_(2)Se/WSe_(2)heterojunction prepared by us has a typeⅡband alignment,which can vastly suppress the channel current through the interface barrier so that the Bi_(2)O_(2)Se/WSe_(2)heterojunction device has a large rectification ratio of about 10^(5).Meanwhile,under different gate voltage modulation,the current on/off ratio of the device changes by nearly five orders of magnitude,and the maximum current on/off ratio is expected to be achieved 106.The photocurrent measurement reveals the behavior of recombination and space charge confinement,further verifying the bidirectional rectification behavior of heterojunctions,and it also exhibits excellent performance in light response.In the future,Bi_(2)O_(2)Se/WSe_(2)heterojunction field-effect transistors have great potential to reduce the volume of integrated circuits as a bidirectional controlled switching device.
基金financially supported by the National Natural Science Foundation of China (No.52106259)the Fundamental Research Funds for the Central Universities (2024MS013)Key Research and Development Program of Shaanxi (Program No.2022LL-JB-08)。
文摘Green hydrogen is urgently required for sustainable development of human beings and rational construction of heterostructures holds great promising for photocatalytic hydrogen generation.Herein,2D/2D WSe_(2)/ZnIn_(2)S_(4) heterostructures with strong hetero-interface interaction and abundant contact were constructed via an impregnation-annealing strategy.Efficient charge transfer from ZnIn_(2)S_(4) to WSe_(2)was evidenced by transient absorption spectroscopy in crafted heterostructures owing to the tight and2D face-to-face contact.As a result,the prepared WSe_(2)/ZnIn_(2)S_(4) heterostructures exhibited boosted photocatalytic performance and a highest hydrogen evolution rate of 3.377 mmol/(g h)was achieved with an apparent quantum yield of 45.7%at 420 nm.The work not only provides new strategies to achieve efficient 2D/2D heterostructures but also paves the way for the development of green hydrogen in the future.
文摘Polarization-resolved photodetectors,a significant branch of photodetection,can more effectively distinguish the target from the background by exploiting polarization-sensitive characteristics.However,due to the absence of intrinsic polarized absorption properties of many materials,there is still a great challenge to develop the high-performance polarization-resolved photodetectors.Here,we report a van der Waals heterojunction(vdWH)ReSe_(2)/WSe_(2)photodetector,which performs a high responsivity of~0.28 A/W and a high detectivity of 1.1×10^(12)Jones under the illumination of 520 nm laser at room temperature.Remarkably,scanning photocurrent mapping(SPCM)measurements demonstrate the photoresponse of devices closely depend on the polarized angle of the incident light,indicating the effective polarized light detection.This work paves the way to develop high-performance polarization-resolved photodetectors based on two-dimensional(2D)materials.
文摘过渡金属硫化物(transition metal dichalcogenides,TMDs)具有优异的光学、电学性能,其中,二维WSe_(2)薄膜作为典型的TMDs类材料之一,凭借其可调控的光学带隙,在光电子器件领域有极大的潜在应用价值。但是,由于单层的WSe_(2)薄膜具有较低的光学吸收截面,对于光的吸收效率较弱,限制了其在光电器件中的应用发展。因此,如何提高单层WSe_(2)薄膜的光吸收和光发射效率成为了人们的研究热点。本文将单层WSe_(2)薄膜作为研究对象构建了Au膜-WSe_(2)复合结构,通过显微光致发光光谱分析其光学性能,分别对比了Au膜-WSe_(2)交界处和Au膜-WSe_(2)复合区域与纯WSe_(2)区域的发光特性,研究表明Au膜与WSe_(2)薄膜直接接触发生了荧光淬灭效应,发光强度减弱;而在两者交界处,受到金属表面等离极化激元效应的作用,交界处的发光强度有明显的增强;为了解释这现象,本文建立了相应的物理模型来解释Au膜-WSe_(2)复合结构的发光特性。
