Low-temperature processed electron transport layer(ETL)of TiO_(2)that is widely used in planar perovskite solar cells(PSCs)has inherent low carrier mobility,resulting in insufficient photogenerated elec-tron transport...Low-temperature processed electron transport layer(ETL)of TiO_(2)that is widely used in planar perovskite solar cells(PSCs)has inherent low carrier mobility,resulting in insufficient photogenerated elec-tron transport and thus recombination loss at buried interface.Herein,we demonstrate an effective strategy of laser embedding of p-n homojunctions in the TiO_(2)ETL to accelerate electron transport in PSCs,through localized build-in electric fields that enables boosted electron mobility by two orders of magnitude.Such embedding is found significantly helpful for not only the enhanced crystallization quality of TiO_(2)ETL,but the fabrication of perovskite films with larger-grain and the less-trap-states.The embedded p-n homojunction enables also the modulation of interfacial energy level between perovskite layers and ETLs,favoring for the reduced voltage deficit of PSCs.Benefiting from these merits,the formamidinium lead iodide(FAPbI_(3))PSCs employing such ETLs deliver a champion efficiency of 25.50%,along with much-improved device stability under harsh conditions,i.e.,maintain over 95%of their initial efficiency after operation at maximum power point under continuous heat and illumination for 500 h,as well as mixed-cation PSCs with a champion efficiency of 22.02%and over 3000 h of ambient storage under humidity stability of 40%.Present study offers new possibilities of regulating charge transport layers via p-n homojunction embedding for high performance optoelectronics.展开更多
Ternary transition metal dichalcogenide alloys with spatially graded bandgaps are an emerging class of two-dimensional materials with unique features,which opens up new potential for device applications.Here,visible–...Ternary transition metal dichalcogenide alloys with spatially graded bandgaps are an emerging class of two-dimensional materials with unique features,which opens up new potential for device applications.Here,visible–near-infrared and self-powered phototransistors based on spatially bandgap-graded MoS2(1−x)Se2x alloys,synthesized by a simple and controllable chemical solution deposition method,are reported.The graded bandgaps,arising from the spatial grading of Se composition and thickness within a single domain,are tuned from 1.83 to 1.73 eV,leading to the formation of a homojunction with a builtin electric field.Consequently,a strong and sensitive gate-modulated photovoltaic effect is demonstrated,enabling the homojunction phototransistors at zero bias to deliver a photoresponsivity of 311 mA W−1,a specific detectivity up to^10^11 Jones,and an on/off ratio up to^10^4.Remarkably,when illuminated by the lights ranging from 405 to 808 nm,the biased devices yield a champion photoresponsivity of 191.5 A W−1,a specific detectivity up to^1012 Jones,a photoconductive gain of 10^6–10^7,and a photoresponsive time in the order of^50 ms.These results provide a simple and competitive solution to the bandgap engineering of two-dimensional materials for device applications without the need for p–n junctions.展开更多
Bi2O2Se thin film could be one of the promising material candidates for the next-generation electronic and optoelectronic applications. However, the performance of Bi2O2Se thin film-based device is not fully explored ...Bi2O2Se thin film could be one of the promising material candidates for the next-generation electronic and optoelectronic applications. However, the performance of Bi2O2Se thin film-based device is not fully explored in the photodetecting area. Considering the fact that the electrical properties such as carrier mobility, work function, and energy band structure of Bi2O2Se are thickness-dependent, the in-plane Bi2O2Se homojunctions consisting of layers with different thicknesses are successfully synthesized by the chemical vapor deposition(CVD) method across the terraces on the mica substrates,where terraces are created in the mica surface layer peeling off process. In this way, effective internal electrical fields are built up along the Bi2O2Se homojunctions, exhibiting diode-like rectification behavior with an on/off ratio of 102, what is more, thus obtained photodetectors possess highly sensitive and ultrafast features, with a maximum photoresponsivity of 2.5 A/W and a lifetime of 4.8 μs. Comparing with the Bi2O2Se uniform thin films, the photo-electric conversion efficiency is greatly improved for the in-plane homojunctions.展开更多
A novel visible light‐responsive homogeneous catalyst based on Bi2WO6 quantum dots(QDs‐BWO)/Bi2WO6 nanosheets(N‐BWO)was successfully fabricated through a simple hydrothermal method.A variety of techniques were empl...A novel visible light‐responsive homogeneous catalyst based on Bi2WO6 quantum dots(QDs‐BWO)/Bi2WO6 nanosheets(N‐BWO)was successfully fabricated through a simple hydrothermal method.A variety of techniques were employed to investigate the morphology,structure,and electronic properties of the samples.The photocatalytic performance of the QDs/N‐BWO materials was investigated by monitoring the degradation of 4‐chlorophenol and rhodamine B under visible light irradiation.The as‐fabricated QDs/N‐BWO materials showed higher photocatalytic activity than both QDs‐BWO and N‐BWO.The results reveal that the incorporation of the QDs improved the separation efficiency of electron‐hole pairs,leading to enhanced photocatalytic activity.Moreover,the results of quenching experiments show that·O2– species played a major role in the degradation process.This work provides an important reference for the fabrication of homogeneous catalysts with high performance in the degradation of different types of pollutants.展开更多
In this study,Ni_(2)P-Cd_(0.9)Zn_(0.1)S(NPCZS)composites were synthesized by coupling tetrapod bundle Cd_(0.9)Zn_(0.1)S(CZS)and coralline-like Ni_(2)P(NP)via a simple calcination method.CZS shows outstanding activity ...In this study,Ni_(2)P-Cd_(0.9)Zn_(0.1)S(NPCZS)composites were synthesized by coupling tetrapod bundle Cd_(0.9)Zn_(0.1)S(CZS)and coralline-like Ni_(2)P(NP)via a simple calcination method.CZS shows outstanding activity in photocatalytic hydrogen evolution(1.31 mmol h^(‒1)),owing to its unique morphology and heterophase homojunctions(ZB/WZ),which accelerate the separation and transfer of photogenerated charges.After coupling with NP,the photoactivity of NPCZS was enhanced,and the maximum hydrogen evolution rate of 1.88 mmol h^(‒1)was reached at a NP content of 12 wt%,which was 1.43 times higher than that of pure CZS.The experimental results of the photocatalytic activity,viz.photoluminescence spectra,surface photovoltage spectra,and electrochemical test showed that the enhanced photoactivity of NPCZS should be attributed to the synergistic effects of the novel tetrapod-bundle morphology,heterophase homojunctions,and decoration of the NP co-catalyst.Moreover,the as-prepared NPCZS composites exhibited excellent photostability and recyclability.Herein,we propose a possible mechanism for the enhanced photocatalytic activity.展开更多
The density functional theory method is utilized to verify the electronic structures of SiC nanotubes(SiCNTs) and SiC nanoribbons(SiCNRs) one-dimensional(1D) van der Waals homojunctions(vdWh) under an applied axial st...The density functional theory method is utilized to verify the electronic structures of SiC nanotubes(SiCNTs) and SiC nanoribbons(SiCNRs) one-dimensional(1D) van der Waals homojunctions(vdWh) under an applied axial strain and an external electric field. According to the calculated results, the SiCNTs/SiCNRs 1D vdWhs are direct semiconductors with a type-II band alignment and robust electronic structures with different diameters or widths. Furthermore,the SiCNTs/SiCNRs 1D vdWhs are direct semiconductors with a type-I band alignment, respectively, in a range of[-0.3,-0.1] V/A and [0.1, 0.3] V/A and change into metal when the electric field intensity is equal to or higher than0.4 V/A. Interestingly, the SiCNTs/SiCNRs 1D vdWhs have robust electronic structures under axial strain. These findings demonstrate theoretically that the SiCNTs/SiCNRs 1D vdWhs can be employed in nanoelectronics devices.展开更多
为了开发高效的太阳能冷却技术,建立了一个由光伏(photovoltaic,PV)模块和基于范德华异质结构(van der Waals heterostructure,vdWH)的热离子制冷器(thermionic refrigerator,TIR)组成的新型耦合系统。在充分考虑内部和外部的不可逆因...为了开发高效的太阳能冷却技术,建立了一个由光伏(photovoltaic,PV)模块和基于范德华异质结构(van der Waals heterostructure,vdWH)的热离子制冷器(thermionic refrigerator,TIR)组成的新型耦合系统。在充分考虑内部和外部的不可逆因素的情况下,建立了耦合系统的理论模型,推导了关键性能指标的数学表达式。在此基础上,研究了耦合系统的一般性能特征,并确定了允许系统运行的电压区域。根据计算,最大制冷量和最大性能系数(coefficient of performance,COP)分别为75.88 W和0.49。此外,还进行了灵敏度分析,以得出关键参数对整体性能影响的规律和大小,包括太阳辐照度、有效肖特基势垒高度、层间热阻、外部热阻、热泄漏热阻和热库温度。所得结果可能有助于实际耦合系统的设计和运行。展开更多
Niobium pentoxide(Nb_(2)O_(5))is deemed one of the promising anode materials for lithium-ion batteries(LIBs)for its outstanding intrinsic fast Li-(de)intercalation kinetics.The specific capacity,however,is still limit...Niobium pentoxide(Nb_(2)O_(5))is deemed one of the promising anode materials for lithium-ion batteries(LIBs)for its outstanding intrinsic fast Li-(de)intercalation kinetics.The specific capacity,however,is still limited,because the(de)intercalation of excessive Li-ions brings the undesired stress to damage Nb_(2)O_(5) crystals.To increase the capacity of Nb_(2)O_(5) and alleviate the lattice distortion caused by stress,numerous homogeneous H-and M-phases junction interfaces were proposed to produce coercive stress within theNb_(2)O_(5)crystals.Such interfaces bring about rich oxygen vacancies with structural shrinkage tendency,which pre-generate coercive stress to resist the expansion stress caused by excessive Li-ions intercalation.Therefore,the synthesized Nb_(2)O_(5) achieves the highest lithium storage capacity of 315 mA h g−1 to date,and exhibits high-rate performance(118 mA h g^(-1) at 20 C)as well as excellent cycling stability(138 mA h g^(-1) at 10 C after 600 cycles).展开更多
The proper bandgap and exceptional photostability enable CsPbI_(3) as a potential candidate for indoor photovoltaics(IPVs),but indoor power conversion efficiency(PCE) is impeded by serious nonradiative recombination s...The proper bandgap and exceptional photostability enable CsPbI_(3) as a potential candidate for indoor photovoltaics(IPVs),but indoor power conversion efficiency(PCE) is impeded by serious nonradiative recombination stemming from challenges in incomplete DMAPbI_(3) conversion and lattice structure distortion.Here,the coplanar symmetric structu re of hexyl sulfide(HS) is employed to functionalize the CsPbI_(3) layer for fabricating highly efficient IPVs.The hydrogen bond between HS and DMAI promotes the conversion of DMAPbI_(3) to CsPbI_(3),while the copianar symmetric structure enhances crystalline order.Simultaneously,surface sulfidation during HS-induced growth results in the in situ formation of PbS,spontaneously creating a CsPbI_(3) N-P homojunction to enhance band alignment and carrier mobility.As a result,the CsPbI_(3)&HS devices achieve an impressive indoor PCE of 39.90%(P_(in):334.6 μW cm^(-2),P_(out):133.5 μW cm^(-2)) under LED@2968 K,1062 lux,and maintain over 90% initial PCE for 800 h at ^(3)0% air ambient humidity.展开更多
基金financially supported by the project of the National Natural Science Foundation of China(52202115 and 52172101)the China Postdoctoral Science Foundation(2022M722586)+2 种基金the Natural Science Foundation of Chongqing,China(CSTB2022NSCQ-MSX1085)the Shaanxi Science and Technology Innovation Team(2023-CX-TD-44)the Fundamental Research Funds for the Central Universities(3102019JC005 and G2022KY0604)。
文摘Low-temperature processed electron transport layer(ETL)of TiO_(2)that is widely used in planar perovskite solar cells(PSCs)has inherent low carrier mobility,resulting in insufficient photogenerated elec-tron transport and thus recombination loss at buried interface.Herein,we demonstrate an effective strategy of laser embedding of p-n homojunctions in the TiO_(2)ETL to accelerate electron transport in PSCs,through localized build-in electric fields that enables boosted electron mobility by two orders of magnitude.Such embedding is found significantly helpful for not only the enhanced crystallization quality of TiO_(2)ETL,but the fabrication of perovskite films with larger-grain and the less-trap-states.The embedded p-n homojunction enables also the modulation of interfacial energy level between perovskite layers and ETLs,favoring for the reduced voltage deficit of PSCs.Benefiting from these merits,the formamidinium lead iodide(FAPbI_(3))PSCs employing such ETLs deliver a champion efficiency of 25.50%,along with much-improved device stability under harsh conditions,i.e.,maintain over 95%of their initial efficiency after operation at maximum power point under continuous heat and illumination for 500 h,as well as mixed-cation PSCs with a champion efficiency of 22.02%and over 3000 h of ambient storage under humidity stability of 40%.Present study offers new possibilities of regulating charge transport layers via p-n homojunction embedding for high performance optoelectronics.
基金supported by Grants from the UK EPSRC Future Compound Semiconductor Manufacturing Hub(EP/P006973/1)the financial support from EPSRC(EP/L018330/1,EP/N032888/1)+3 种基金the U.S.Army Research Laboratory under Cooperative Agreement Number W911NF-16-2-0120the “973 Program—the National Basic Research Program of China” Special Funds for the Chief Young Scientis(2015CB358600)the Excellent Young Scholar Fund from National Natural Science Foundation of China(21422103)the China Scholarship Council(CSC)
文摘Ternary transition metal dichalcogenide alloys with spatially graded bandgaps are an emerging class of two-dimensional materials with unique features,which opens up new potential for device applications.Here,visible–near-infrared and self-powered phototransistors based on spatially bandgap-graded MoS2(1−x)Se2x alloys,synthesized by a simple and controllable chemical solution deposition method,are reported.The graded bandgaps,arising from the spatial grading of Se composition and thickness within a single domain,are tuned from 1.83 to 1.73 eV,leading to the formation of a homojunction with a builtin electric field.Consequently,a strong and sensitive gate-modulated photovoltaic effect is demonstrated,enabling the homojunction phototransistors at zero bias to deliver a photoresponsivity of 311 mA W−1,a specific detectivity up to^10^11 Jones,and an on/off ratio up to^10^4.Remarkably,when illuminated by the lights ranging from 405 to 808 nm,the biased devices yield a champion photoresponsivity of 191.5 A W−1,a specific detectivity up to^1012 Jones,a photoconductive gain of 10^6–10^7,and a photoresponsive time in the order of^50 ms.These results provide a simple and competitive solution to the bandgap engineering of two-dimensional materials for device applications without the need for p–n junctions.
基金Project supported by the National Natural Science Foundation of China(Grant No.61705066)the Open Fund of State Key Laboratory of Information Photonics and Optical Communications(Beijing University of Posts and Telecommunications),China(Grant No.IPOC2018B004)the National Key Research and Development Program,China(Grant No.2016YFA0202401)
文摘Bi2O2Se thin film could be one of the promising material candidates for the next-generation electronic and optoelectronic applications. However, the performance of Bi2O2Se thin film-based device is not fully explored in the photodetecting area. Considering the fact that the electrical properties such as carrier mobility, work function, and energy band structure of Bi2O2Se are thickness-dependent, the in-plane Bi2O2Se homojunctions consisting of layers with different thicknesses are successfully synthesized by the chemical vapor deposition(CVD) method across the terraces on the mica substrates,where terraces are created in the mica surface layer peeling off process. In this way, effective internal electrical fields are built up along the Bi2O2Se homojunctions, exhibiting diode-like rectification behavior with an on/off ratio of 102, what is more, thus obtained photodetectors possess highly sensitive and ultrafast features, with a maximum photoresponsivity of 2.5 A/W and a lifetime of 4.8 μs. Comparing with the Bi2O2Se uniform thin films, the photo-electric conversion efficiency is greatly improved for the in-plane homojunctions.
文摘A novel visible light‐responsive homogeneous catalyst based on Bi2WO6 quantum dots(QDs‐BWO)/Bi2WO6 nanosheets(N‐BWO)was successfully fabricated through a simple hydrothermal method.A variety of techniques were employed to investigate the morphology,structure,and electronic properties of the samples.The photocatalytic performance of the QDs/N‐BWO materials was investigated by monitoring the degradation of 4‐chlorophenol and rhodamine B under visible light irradiation.The as‐fabricated QDs/N‐BWO materials showed higher photocatalytic activity than both QDs‐BWO and N‐BWO.The results reveal that the incorporation of the QDs improved the separation efficiency of electron‐hole pairs,leading to enhanced photocatalytic activity.Moreover,the results of quenching experiments show that·O2– species played a major role in the degradation process.This work provides an important reference for the fabrication of homogeneous catalysts with high performance in the degradation of different types of pollutants.
文摘In this study,Ni_(2)P-Cd_(0.9)Zn_(0.1)S(NPCZS)composites were synthesized by coupling tetrapod bundle Cd_(0.9)Zn_(0.1)S(CZS)and coralline-like Ni_(2)P(NP)via a simple calcination method.CZS shows outstanding activity in photocatalytic hydrogen evolution(1.31 mmol h^(‒1)),owing to its unique morphology and heterophase homojunctions(ZB/WZ),which accelerate the separation and transfer of photogenerated charges.After coupling with NP,the photoactivity of NPCZS was enhanced,and the maximum hydrogen evolution rate of 1.88 mmol h^(‒1)was reached at a NP content of 12 wt%,which was 1.43 times higher than that of pure CZS.The experimental results of the photocatalytic activity,viz.photoluminescence spectra,surface photovoltage spectra,and electrochemical test showed that the enhanced photoactivity of NPCZS should be attributed to the synergistic effects of the novel tetrapod-bundle morphology,heterophase homojunctions,and decoration of the NP co-catalyst.Moreover,the as-prepared NPCZS composites exhibited excellent photostability and recyclability.Herein,we propose a possible mechanism for the enhanced photocatalytic activity.
基金Project supported by the National Natural Science Foundation of China(Grant No.11864011)the Youth Project of Scientific and Technological Research Program of Chongqing Education Commission,China(Grant Nos.KJQN202001207 and KJQN202101204)the Fund from the Educational Commission of Hubei Province,China(Grant No.T201914)。
文摘The density functional theory method is utilized to verify the electronic structures of SiC nanotubes(SiCNTs) and SiC nanoribbons(SiCNRs) one-dimensional(1D) van der Waals homojunctions(vdWh) under an applied axial strain and an external electric field. According to the calculated results, the SiCNTs/SiCNRs 1D vdWhs are direct semiconductors with a type-II band alignment and robust electronic structures with different diameters or widths. Furthermore,the SiCNTs/SiCNRs 1D vdWhs are direct semiconductors with a type-I band alignment, respectively, in a range of[-0.3,-0.1] V/A and [0.1, 0.3] V/A and change into metal when the electric field intensity is equal to or higher than0.4 V/A. Interestingly, the SiCNTs/SiCNRs 1D vdWhs have robust electronic structures under axial strain. These findings demonstrate theoretically that the SiCNTs/SiCNRs 1D vdWhs can be employed in nanoelectronics devices.
文摘为了开发高效的太阳能冷却技术,建立了一个由光伏(photovoltaic,PV)模块和基于范德华异质结构(van der Waals heterostructure,vdWH)的热离子制冷器(thermionic refrigerator,TIR)组成的新型耦合系统。在充分考虑内部和外部的不可逆因素的情况下,建立了耦合系统的理论模型,推导了关键性能指标的数学表达式。在此基础上,研究了耦合系统的一般性能特征,并确定了允许系统运行的电压区域。根据计算,最大制冷量和最大性能系数(coefficient of performance,COP)分别为75.88 W和0.49。此外,还进行了灵敏度分析,以得出关键参数对整体性能影响的规律和大小,包括太阳辐照度、有效肖特基势垒高度、层间热阻、外部热阻、热泄漏热阻和热库温度。所得结果可能有助于实际耦合系统的设计和运行。
基金supported by the National Natural Science Foundation of China(Nos.51673199,51972301,51677176)the Youth Innovation Promotion Association of CAS(2015148,Y201940)+2 种基金the Youth Innovation Foundation of DICP(ZZBS201615,ZZBS201708)the Dalian Outstanding Young Scientific Talent(2018RJ03)the National Key Research and Development Project(2019YFA0705600)。
文摘Niobium pentoxide(Nb_(2)O_(5))is deemed one of the promising anode materials for lithium-ion batteries(LIBs)for its outstanding intrinsic fast Li-(de)intercalation kinetics.The specific capacity,however,is still limited,because the(de)intercalation of excessive Li-ions brings the undesired stress to damage Nb_(2)O_(5) crystals.To increase the capacity of Nb_(2)O_(5) and alleviate the lattice distortion caused by stress,numerous homogeneous H-and M-phases junction interfaces were proposed to produce coercive stress within theNb_(2)O_(5)crystals.Such interfaces bring about rich oxygen vacancies with structural shrinkage tendency,which pre-generate coercive stress to resist the expansion stress caused by excessive Li-ions intercalation.Therefore,the synthesized Nb_(2)O_(5) achieves the highest lithium storage capacity of 315 mA h g−1 to date,and exhibits high-rate performance(118 mA h g^(-1) at 20 C)as well as excellent cycling stability(138 mA h g^(-1) at 10 C after 600 cycles).
基金financial support from the Natural Science Foundation of Guizhou Province (Grant No. ZK 2024-087)Natural Science Foundation of China (no. 22005071)。
文摘The proper bandgap and exceptional photostability enable CsPbI_(3) as a potential candidate for indoor photovoltaics(IPVs),but indoor power conversion efficiency(PCE) is impeded by serious nonradiative recombination stemming from challenges in incomplete DMAPbI_(3) conversion and lattice structure distortion.Here,the coplanar symmetric structu re of hexyl sulfide(HS) is employed to functionalize the CsPbI_(3) layer for fabricating highly efficient IPVs.The hydrogen bond between HS and DMAI promotes the conversion of DMAPbI_(3) to CsPbI_(3),while the copianar symmetric structure enhances crystalline order.Simultaneously,surface sulfidation during HS-induced growth results in the in situ formation of PbS,spontaneously creating a CsPbI_(3) N-P homojunction to enhance band alignment and carrier mobility.As a result,the CsPbI_(3)&HS devices achieve an impressive indoor PCE of 39.90%(P_(in):334.6 μW cm^(-2),P_(out):133.5 μW cm^(-2)) under LED@2968 K,1062 lux,and maintain over 90% initial PCE for 800 h at ^(3)0% air ambient humidity.
文摘采用化学气相沉积方法,利用Sb_2O_3/Sn O作为源材料,在蓝宝石衬底上制备出不同Sb掺杂量的SnO_2薄膜,并在此基础上制作出p-SnO_2:Sb/n-SnO_2同质p-n结器件.研究表明,随着Sb含量的增加,样品表面变得平滑,晶粒尺寸逐渐增大,且晶体质量有所改善,发现少量Sb的掺入可以起到表面活化剂的作用.Hall测量结果证实适量Sb的掺杂可以使SnO_2呈现p型导电特性,当Sb_2O_3/SnO的质量比为1:5时,其电学参数为最佳值.此外,p-SnO_2:Sb/n-SnO_2同质p-n结器件展现出良好的整流特性,其正向开启电压为3.4 V.
