Multi-energy X-ray detection is sought after for a wide range of applications including medical imaging,security checking and industrial flaw inspection.Perovskite X-ray detectors are superior in terms of high sensiti...Multi-energy X-ray detection is sought after for a wide range of applications including medical imaging,security checking and industrial flaw inspection.Perovskite X-ray detectors are superior in terms of high sensitivity and low detection limit,which lays a foundation for multi-energy discrimination.However,the extended capability of the perovskite detector for multi-energy X-ray detection is challenging and has never been reported.Herein we report the design of vertical matrix perovskite X-ray detectors for multi-energy detection,based on the attenuation behavior of X-ray within the detector and machine learning algorithm.This platform is independent of the complex X-ray source components that constrain the energy discrimination capability.We show that the incident X-ray spectra could be accurately reconstructed from the conversion matrix and measured photocurrent response.Moreover,the detector could produce a set of images containing the density-graded information under single exposure,and locate the concealed position for all low-,medium-and high-density substances.Our findings suggest a new generation of X-ray detectors with features of multi-energy discrimination,density differentiation,and contrast-enhanced imaging.展开更多
Direct X-ray detectors are considered as competitive next-generation X-ray detectors because of their high spatial resolution,high sensitivity,and simple device configuration.However,their potential is largely limited...Direct X-ray detectors are considered as competitive next-generation X-ray detectors because of their high spatial resolution,high sensitivity,and simple device configuration.However,their potential is largely limited by the imperfections of traditional materials,such as the low crystallization temperature of α-Se and the low atomic numbers of α-Si and α-Se.Here,we report the Sb_(2)Se_(3) X-ray thin-film detector with a p-n junction structure,which exhibited a sensitivity of 106.3 μC/(Gyair·cm^(2))and response time of<2.5 ms.This decent performance and the various advantages of Sb_(2)Se_(3),such as the average atomic number of 40.8 and μτ product(μ is the mobility,and τ is the carrier lifetime)of 1.29×1O^(-5) cm^(2)/V,indicate its potential for application in X-ray detection.展开更多
Metal halide perovskites(MHPs)have demonstrated excellent performances in detection of X-rays and gamma-rays.Most studies focus on improving the sensitivity of single-pixel MHP detectors.However,little work pays atten...Metal halide perovskites(MHPs)have demonstrated excellent performances in detection of X-rays and gamma-rays.Most studies focus on improving the sensitivity of single-pixel MHP detectors.However,little work pays attention to the dark current,which is crucial for the back-end circuit integration.Herein,the requirement of dark current is quantitatively evaluated as low as 10^(−9)A/cm^(2)for X-ray imagers integrated on pixel circuits.Moreover,through the semiconductor device analysis and simulation,we reveal that the main current compositions of thick perovskite X-ray detectors are the thermionic-emission current(J_(T))and the generation-recombination current(J_(g-r)).The typical observed failures of p-n junctions in thick detectors are caused by the high generation-recombination current due to the band mismatch and interface defects.This work provides a deep insight into the design of high sensitivity and low dark current perovskite X-ray detectors.展开更多
The metal halide perovskites exhibit excellent performance as the direct X-ray detectors owing to their strong absorption capability,long carrier lifetime and diffusion length,radiation ruggedness,etc.For imaging appl...The metal halide perovskites exhibit excellent performance as the direct X-ray detectors owing to their strong absorption capability,long carrier lifetime and diffusion length,radiation ruggedness,etc.For imaging applications,the ionic migration of perovskites and charge sharing effect between the adjacent pixels have a significantly negative impact on the spatial resolution.Herein,for the first time,the porous anodic aluminum oxides(AAO)have been used as a template to grow the CsPbBr2I thick film for the direct X-ray detection.Benefiting from the oxygen passivation effect,the activation energy for ionic migration has been observed to increase to 0.701 eV,whereas the dark current drift(1.01×10^(-5)nA cm^(-1)s^(-1)V^(-1))is one to two orders of magnitude lower than the other lead halide perovskite single crystals and films.Moreover,the AAO insulating wall effectively blocks the charge diffusion effect across a pixel pitch of 10^m.Overall,the findings reported in this study open a new route for reducing the ionic migration and pixel crosstalk,thus,bringing the perovskite X-ray detectors close to the practical applications.展开更多
基金supported by the National Natural Science Foundation of China (51972194, 51602178, 51932004 and 61975098)the 111 Project 2.0 (BP2018013)+3 种基金the National Key Research and Development Program of China (2016YFB1102201 and 2018YFB0406502)the Fundamental Research Funds of Shandong Universitythe State Key Laboratory of Solidification Processing in Northwestern Polytechnical University (NWPU) (SKLSP202019)Shandong Provincial Key Research and Development Program (2018GGX102003)
文摘近年来,全无机无铅卤化物钙钛矿以其良好的环境稳定性和热稳定性、优异的光电性能以及环境友好性而受到广泛关注.本文采用改进的垂直布里奇曼法首次生长出直径12 mm、长度约40 mm、透明性良好的Cs_(3)Bi_(2)Br_(9)单晶.生长的Cs_(3)Bi_(2)Br_(9)单晶的电阻率约为6.8×10^(11)Ωcm,透过率约为80%.在(−120)晶面内,载流子迁移率为0.17 cm^(2)V^(−1)s^(−1),缺陷态密度为9.7×10^(10)cm^(−3).在X射线探测方面,Cs_(3)Bi_(2)Br_(9)单晶最大灵敏度约为230.4μC Gyair−1 cm^(−2);暗电流密度约为17.8 pA mm^(−2),且没有漂移现象,这表明Cs_(3)Bi_(2)Br_(9)单晶具有更小的暗电流噪声,有利于获得更低的检测限.
基金financially supported by the Major State Basic Research Development Program of China(2021YFB3201000)the National Natural Science Foundation of China(62074066,62134003,and 12050005)+2 种基金the Fund for Innovative Research Groups of the Natural Science Foundation of Hubei Province(2021CFA036,2020CFA034)Shenzhen Basic Research Program(JCYJ20200109115212546)the Fundamental Research Funds for the Central Universities HUST(2020JYCXJJ073)。
文摘Multi-energy X-ray detection is sought after for a wide range of applications including medical imaging,security checking and industrial flaw inspection.Perovskite X-ray detectors are superior in terms of high sensitivity and low detection limit,which lays a foundation for multi-energy discrimination.However,the extended capability of the perovskite detector for multi-energy X-ray detection is challenging and has never been reported.Herein we report the design of vertical matrix perovskite X-ray detectors for multi-energy detection,based on the attenuation behavior of X-ray within the detector and machine learning algorithm.This platform is independent of the complex X-ray source components that constrain the energy discrimination capability.We show that the incident X-ray spectra could be accurately reconstructed from the conversion matrix and measured photocurrent response.Moreover,the detector could produce a set of images containing the density-graded information under single exposure,and locate the concealed position for all low-,medium-and high-density substances.Our findings suggest a new generation of X-ray detectors with features of multi-energy discrimination,density differentiation,and contrast-enhanced imaging.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.61725401 and 61904058)the National Key R&D Program of China(No.2016YFA0204000)+3 种基金the Innovation Fund of Wuhan National Laboratory for Optoelectronics(WNLO)the National Postdoctoral Program for Innovative Talent(No.BX20190127)China Postdoctoral Science Foundation Project(No.2019M662623)The authors thank the Analytical and Testing Center of Huazhong University of Science and Technology(HUST)and the facility support of the Center for Nanoscale Characterization and Devices,WNLO-HUST.
文摘Direct X-ray detectors are considered as competitive next-generation X-ray detectors because of their high spatial resolution,high sensitivity,and simple device configuration.However,their potential is largely limited by the imperfections of traditional materials,such as the low crystallization temperature of α-Se and the low atomic numbers of α-Si and α-Se.Here,we report the Sb_(2)Se_(3) X-ray thin-film detector with a p-n junction structure,which exhibited a sensitivity of 106.3 μC/(Gyair·cm^(2))and response time of<2.5 ms.This decent performance and the various advantages of Sb_(2)Se_(3),such as the average atomic number of 40.8 and μτ product(μ is the mobility,and τ is the carrier lifetime)of 1.29×1O^(-5) cm^(2)/V,indicate its potential for application in X-ray detection.
基金supported by the Major State Basic Research Development Program of China(No.2021YFB3201000)the National Natural Science Foundation of China(Grant Nos.62074066,62134003,and 12050005)+2 种基金the Fund for Innovative Research Groups of the Natural Science Foundation of Hubei Province(Nos.2021CFA036 and 2020CFA034)Shenzhen Basic Research Program(No.JCYJ20200109115212546)the Fundamental Research Funds for the Central Universities.
文摘Metal halide perovskites(MHPs)have demonstrated excellent performances in detection of X-rays and gamma-rays.Most studies focus on improving the sensitivity of single-pixel MHP detectors.However,little work pays attention to the dark current,which is crucial for the back-end circuit integration.Herein,the requirement of dark current is quantitatively evaluated as low as 10^(−9)A/cm^(2)for X-ray imagers integrated on pixel circuits.Moreover,through the semiconductor device analysis and simulation,we reveal that the main current compositions of thick perovskite X-ray detectors are the thermionic-emission current(J_(T))and the generation-recombination current(J_(g-r)).The typical observed failures of p-n junctions in thick detectors are caused by the high generation-recombination current due to the band mismatch and interface defects.This work provides a deep insight into the design of high sensitivity and low dark current perovskite X-ray detectors.
基金the Center for Nanoscale Characterization and Devices,WNLO.This work was supported by the National Natural Science Foundation of China(Grants No.62074066,51761145048,61725401,51702107,11674237,and 51602211),the seed fund of WNLO,and the Fundamental Research Funds for the Central Universities.
文摘The metal halide perovskites exhibit excellent performance as the direct X-ray detectors owing to their strong absorption capability,long carrier lifetime and diffusion length,radiation ruggedness,etc.For imaging applications,the ionic migration of perovskites and charge sharing effect between the adjacent pixels have a significantly negative impact on the spatial resolution.Herein,for the first time,the porous anodic aluminum oxides(AAO)have been used as a template to grow the CsPbBr2I thick film for the direct X-ray detection.Benefiting from the oxygen passivation effect,the activation energy for ionic migration has been observed to increase to 0.701 eV,whereas the dark current drift(1.01×10^(-5)nA cm^(-1)s^(-1)V^(-1))is one to two orders of magnitude lower than the other lead halide perovskite single crystals and films.Moreover,the AAO insulating wall effectively blocks the charge diffusion effect across a pixel pitch of 10^m.Overall,the findings reported in this study open a new route for reducing the ionic migration and pixel crosstalk,thus,bringing the perovskite X-ray detectors close to the practical applications.
