Metal halide perovskites,particularly the quasi-two-dimensional perovskite subclass,have exhibited considerable potential for next-generation electroluminescent materials for lighting and display.Nevertheless,the pres...Metal halide perovskites,particularly the quasi-two-dimensional perovskite subclass,have exhibited considerable potential for next-generation electroluminescent materials for lighting and display.Nevertheless,the presence of defects within these perovskites has a substantial influence on the emission efficiency and durability of the devices.In this study,we revealed a synergistic passivation mechanism on perovskite films by using a dual-functional compound of potassium bromide.The dual functional potassium bromide on the one hand can passivate the defects of halide vacancies with bromine anions and,on the other hand,can screen the charged defects at the grain boundaries with potassium cations.This approach effectively reduces the probability of carriers quenching resulting from charged defects capture and consequently enhances the radiative recombination efficiency of perovskite thin films,leading to a significant enhancement of photoluminescence quantum yield to near-unity values(95%).Meanwhile,the potassium bromide treatment promoted the growth of homogeneous and smooth film,facilitating the charge carrier injection in the devices.Consequently,the perovskite light-emitting diodes based on this strategy achieve a maximum external quantum efficiency of~21%and maximum luminance of~60,000 cd m^(-2).This work provides a deeper insight into the passivation mechanism of ionic compound additives in perovskite with the solution method.展开更多
GaAs nanowires(NWs)are ideal materials for preparing near-infrared photodetectors owing to their high charge carrier mobility and direct band gap.Although the performance of GaAs NW photodetectors can be enhanced by s...GaAs nanowires(NWs)are ideal materials for preparing near-infrared photodetectors owing to their high charge carrier mobility and direct band gap.Although the performance of GaAs NW photodetectors can be enhanced by surface passivation or doping,it still cannot meet the requirement for applications.In this paper we propose a method to greatly improve the performances of GaAs NW photodetectors by hot-hole injection via surface plasmon polaritons.In this case,the responsivity of a single GaAs NW photodetector is increased by a fact of 3.2 to 6.56 A·W^(-1) by attaching capsulelike Au nanoparticles to its surface.This research uses an efficient route to improve the NW photocurrent,which is also important for the development of a high-performance near-infrared NW photodetecor.展开更多
Self-powered photodetectors based on nanomaterials have attracted lots of attention for several years due to their various advantages.In this paper,we report a high performance Cu2O/ZnO self-powered photodetector fabr...Self-powered photodetectors based on nanomaterials have attracted lots of attention for several years due to their various advantages.In this paper,we report a high performance Cu2O/ZnO self-powered photodetector fabricated by using electrochemical deposition.ZnO nanowires arrays grown on indium-tin-oxide glass are immersed in Cu2O film to construct type-Ⅱband structure.The Cu2O/ZnO photodetector exhibits a responsivity of 0.288 mA/W at 596 nm without bias.Compared with Cu2O photoconductive detector,the responsivity of the Cu2O/ZnO self-powered photodetector is enhanced by about two times at 2 V bias.It is attributed to the high power conversion efficiency and the efficient separation of the photogenerated electron-hole pairs,which are provided by the heterojunction.The outstanding comprehensive performances make the Cu2O film/ZnO nanowires self-powered photodetector have great potential applications.展开更多
Vanadium oxide films were grown by atomic layer deposition using the tetrakis[ethylmethylamino] vanadium as the vanadium precursor and H2O as the oxide source. The effect of the source temperature on the quality of va...Vanadium oxide films were grown by atomic layer deposition using the tetrakis[ethylmethylamino] vanadium as the vanadium precursor and H2O as the oxide source. The effect of the source temperature on the quality of vanadium oxide films and valence state was investigated. The crystallinity, surface morphology, film thickness, and photoelectric properties of the films were characterized by x-ray diffraction, atomic force microscope, scanning electron microscope, I–V characteristics curves, and UV–visible spectrophotometer. By varying the source temperature, the content of V6O11, VO2, and V6O13 in the vanadium oxide film increased, that is, as the temperature increased, the average oxidation state generally decreased to a lower value, which is attributed to the rising of the vapor pressure and the change of the ionization degree for organometallics. Meanwhile, the root-mean-square roughness decreased and the metal–insulator transition temperature reduced. Our study is great significance for the fabrication of vanadium oxide films by atomic layer deposition.展开更多
All inorganic perovskite CsPbX_(3)with excellent optical properties and a tunable bandgap is a potential candidate for optoelectronic applications,and the amplified spontaneous emission(ASE)is normally reported in low...All inorganic perovskite CsPbX_(3)with excellent optical properties and a tunable bandgap is a potential candidate for optoelectronic applications,and the amplified spontaneous emission(ASE)is normally reported in low-dimensional structures where the quantum confinement enhances ASE.Herein,we not only demonstrate the ASE in millimeter size CsPbCl_(x)Br_(3-x)crystal with a high defect concentration,but also tune the emission wavelength from the green band to blue band through the ion exchange of Br with Cl.The ASE centered at∼456 nm is probed at 50 K with a threshold of 106μJ/cm 2.Furthermore,a metal-semiconductor-metal(MSM)structure CsPbCl_(x)Br_(3-x)photodetector is fabricated and shows a distinct response to lights from UV to the blue band;the response spectrum range is quite different from the narrow band(∼30 nm)response of the CsPbBr_(3)photodetector induced by a charge collection narrowing(CCN)mechanism.The CsPbCl_(x)Br_(3-x)photodetector also exhibits fast response speeds with a rise time of 96μs and a decay time of 34μs,indicating the defects have limited influence on the transportation speed of the photo-generated carriers.展开更多
We developed a hybrid structure photodetector combining one-dimensional(1D)inorganic GaAs nanowires and two-dimensional(2D)organic perovskite materials,which can achieve various performance enhancements using a relati...We developed a hybrid structure photodetector combining one-dimensional(1D)inorganic GaAs nanowires and two-dimensional(2D)organic perovskite materials,which can achieve various performance enhancements using a relatively simple structure.Via the optical absorption enhancement of perovskite and the type-II energy band structure formed by the heterostructure,the responsivity and detectivity of the photodetector from ultraviolet(UV)to visible(Vis)wavelengths are significantly enhanced,reaching 75 A/W and 1.49×10^(11)Jones,respectively.The response time of the photodetector was significantly decreased by 3 orders,from 785 ms to 0.5 ms,and the dark current was further reduced to 237 fA.A photodetector was prepared with enhanced responsivity and ultrafast response time in the multiband region from the UV to Vis wavelength.To the best of our knowledge,this is the first time to combine inorganicⅢ-ⅤGaAs nanomaterials with organic perovskite materials,which verifies the effective combination of inorganic and organic materials in a mixed dimension.The excellent photoelectric performance of the perovskite/GaAs-nanowire hybrid structure photodetector makes it a potential candidate material for a wide range of photoelectric applications such as multiband photodetection.展开更多
基金supported by the Science and Technology Development Fund,Macao SAR(File no.FDCT-0082/2021/A2,0010/2022/AMJ,006/2022/ALC)UM's research fund(File no.MYRG2022-00241-IAPME,MYRGCRG2022-00009-FHS)+2 种基金the research fund from Wuyi University(EF38/IAPME-XGC/2022/WYU)the Natural Science Foundation of China(61935017,62175268)Science,Technology and Innovation Commission of Shenzhen Municipality(Project Nos.JCYJ20220530113015035,JCYJ20210324120204011,and KQTD2015071710313656).
文摘Metal halide perovskites,particularly the quasi-two-dimensional perovskite subclass,have exhibited considerable potential for next-generation electroluminescent materials for lighting and display.Nevertheless,the presence of defects within these perovskites has a substantial influence on the emission efficiency and durability of the devices.In this study,we revealed a synergistic passivation mechanism on perovskite films by using a dual-functional compound of potassium bromide.The dual functional potassium bromide on the one hand can passivate the defects of halide vacancies with bromine anions and,on the other hand,can screen the charged defects at the grain boundaries with potassium cations.This approach effectively reduces the probability of carriers quenching resulting from charged defects capture and consequently enhances the radiative recombination efficiency of perovskite thin films,leading to a significant enhancement of photoluminescence quantum yield to near-unity values(95%).Meanwhile,the potassium bromide treatment promoted the growth of homogeneous and smooth film,facilitating the charge carrier injection in the devices.Consequently,the perovskite light-emitting diodes based on this strategy achieve a maximum external quantum efficiency of~21%and maximum luminance of~60,000 cd m^(-2).This work provides a deeper insight into the passivation mechanism of ionic compound additives in perovskite with the solution method.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.62074018,12074045,61904017and 11804335)the Developing Project of Science and Technology of Jilin Province,China(Grant No.20200301052RQ)the Project of Education Department of Jilin Province,China(Grant Nos.JJKH20200763KJ and JJKH20210831KJ)。
文摘GaAs nanowires(NWs)are ideal materials for preparing near-infrared photodetectors owing to their high charge carrier mobility and direct band gap.Although the performance of GaAs NW photodetectors can be enhanced by surface passivation or doping,it still cannot meet the requirement for applications.In this paper we propose a method to greatly improve the performances of GaAs NW photodetectors by hot-hole injection via surface plasmon polaritons.In this case,the responsivity of a single GaAs NW photodetector is increased by a fact of 3.2 to 6.56 A·W^(-1) by attaching capsulelike Au nanoparticles to its surface.This research uses an efficient route to improve the NW photocurrent,which is also important for the development of a high-performance near-infrared NW photodetecor.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61704011,61674021,11674038,61574022,and 61904017)the Innovation Foundation of Changchun University of Science and Technology(Grant No.XQNJJ-2018-18).
文摘Self-powered photodetectors based on nanomaterials have attracted lots of attention for several years due to their various advantages.In this paper,we report a high performance Cu2O/ZnO self-powered photodetector fabricated by using electrochemical deposition.ZnO nanowires arrays grown on indium-tin-oxide glass are immersed in Cu2O film to construct type-Ⅱband structure.The Cu2O/ZnO photodetector exhibits a responsivity of 0.288 mA/W at 596 nm without bias.Compared with Cu2O photoconductive detector,the responsivity of the Cu2O/ZnO self-powered photodetector is enhanced by about two times at 2 V bias.It is attributed to the high power conversion efficiency and the efficient separation of the photogenerated electron-hole pairs,which are provided by the heterojunction.The outstanding comprehensive performances make the Cu2O film/ZnO nanowires self-powered photodetector have great potential applications.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11674038,61674021,61704011,and 61904017)the Developing Project of Science and Technology of Jilin Province,China(Grant Nos.20170520118JH and 20160520027JH)the Youth Foundation of Changchun University of Science and Technology(Grant No.XQNJJ-2018-18).
文摘Vanadium oxide films were grown by atomic layer deposition using the tetrakis[ethylmethylamino] vanadium as the vanadium precursor and H2O as the oxide source. The effect of the source temperature on the quality of vanadium oxide films and valence state was investigated. The crystallinity, surface morphology, film thickness, and photoelectric properties of the films were characterized by x-ray diffraction, atomic force microscope, scanning electron microscope, I–V characteristics curves, and UV–visible spectrophotometer. By varying the source temperature, the content of V6O11, VO2, and V6O13 in the vanadium oxide film increased, that is, as the temperature increased, the average oxidation state generally decreased to a lower value, which is attributed to the rising of the vapor pressure and the change of the ionization degree for organometallics. Meanwhile, the root-mean-square roughness decreased and the metal–insulator transition temperature reduced. Our study is great significance for the fabrication of vanadium oxide films by atomic layer deposition.
基金National Natural Science Foundation of China(52172149)Youth S&T Talent Support Programme of Guangdong Provincial Association for Science and Technology(SKXRC202405)Guangdong Provincial Key Laboratory Project(High-Performance Integrated Circuits and Systems Laboratory,2023KSYS003)。
文摘All inorganic perovskite CsPbX_(3)with excellent optical properties and a tunable bandgap is a potential candidate for optoelectronic applications,and the amplified spontaneous emission(ASE)is normally reported in low-dimensional structures where the quantum confinement enhances ASE.Herein,we not only demonstrate the ASE in millimeter size CsPbCl_(x)Br_(3-x)crystal with a high defect concentration,but also tune the emission wavelength from the green band to blue band through the ion exchange of Br with Cl.The ASE centered at∼456 nm is probed at 50 K with a threshold of 106μJ/cm 2.Furthermore,a metal-semiconductor-metal(MSM)structure CsPbCl_(x)Br_(3-x)photodetector is fabricated and shows a distinct response to lights from UV to the blue band;the response spectrum range is quite different from the narrow band(∼30 nm)response of the CsPbBr_(3)photodetector induced by a charge collection narrowing(CCN)mechanism.The CsPbCl_(x)Br_(3-x)photodetector also exhibits fast response speeds with a rise time of 96μs and a decay time of 34μs,indicating the defects have limited influence on the transportation speed of the photo-generated carriers.
基金National Natural Science Foundation of China(11804335,12074045,61904017,62027820)OpenFoundation of Key Laboratory of Laser Technology+2 种基金China North Industries Group Corporation Limited(KLLDT202105)Youth Foundation of ChangchunUniversity of Science and Technology(XQNJJ-2018-18)“111”Project of China(D17017)。
文摘We developed a hybrid structure photodetector combining one-dimensional(1D)inorganic GaAs nanowires and two-dimensional(2D)organic perovskite materials,which can achieve various performance enhancements using a relatively simple structure.Via the optical absorption enhancement of perovskite and the type-II energy band structure formed by the heterostructure,the responsivity and detectivity of the photodetector from ultraviolet(UV)to visible(Vis)wavelengths are significantly enhanced,reaching 75 A/W and 1.49×10^(11)Jones,respectively.The response time of the photodetector was significantly decreased by 3 orders,from 785 ms to 0.5 ms,and the dark current was further reduced to 237 fA.A photodetector was prepared with enhanced responsivity and ultrafast response time in the multiband region from the UV to Vis wavelength.To the best of our knowledge,this is the first time to combine inorganicⅢ-ⅤGaAs nanomaterials with organic perovskite materials,which verifies the effective combination of inorganic and organic materials in a mixed dimension.The excellent photoelectric performance of the perovskite/GaAs-nanowire hybrid structure photodetector makes it a potential candidate material for a wide range of photoelectric applications such as multiband photodetection.
