The solar X-ray detector(SXD)onboard the Macao Science Satellite-1B was designed to monitor solar flare bursts and to study the solar activity in the 25th solar cycle.The SXD includes two parts:a soft X-ray detection ...The solar X-ray detector(SXD)onboard the Macao Science Satellite-1B was designed to monitor solar flare bursts and to study the solar activity in the 25th solar cycle.The SXD includes two parts:a soft X-ray detection unit and a hard X-ray detection unit.Both the soft X-ray detection unit and the hard X-ray detection unit include two collimators,two X-ray detectors(a silicon drift detector and a cadmium-zinc-telluride detector),and a processing circuit.Compared with similar instruments,the energy range of the SXD is wider(1–600 ke V)and the energy resolution is better(150 e V at 5.9 ke V,12%at 59.5 ke V,and 3%at 662 keV).展开更多
X-ray imaging technologies such as digital radiography(DR),is an important aspect of modern non-destructive testing and medical diagnosis.Innovative flexible X-ray detector technologies have recently been proposed and...X-ray imaging technologies such as digital radiography(DR),is an important aspect of modern non-destructive testing and medical diagnosis.Innovative flexible X-ray detector technologies have recently been proposed and are now receiving increasing attention owing to their superior material flexibility compared with traditional flat-panel detectors.This work aims to study these innovative flexible X-ray detectors in terms of their effectiveness in DR imaging,such as detection efficiency and spatial resolution.To achieve this goal,first,a Monte Carlo model was developed and calibrated to an in-lab 150 kV DR imaging system containing a flat-panel X-ray detector.Second,the validated model was updated with various types of flexible X-ray detectors to assess their performance in nearly realistic conditions.Key parameters such as the detection efficiency pertaining to the crystal material and thickness were studied and analyzed across a broader energy range up to 662 keV.Finally,the imaging performance of the different detectors was evaluated and compared to that of the flat-panel detector in the 150 kV DR imaging system.The results show that the flexible detectors such as the CsPbBr3crystal detector deliver promising performance in X-ray imaging and can be applied to a wider range of application scenarios,especially those requiring accurate detection at challenging angles.展开更多
In recent years,two-dimensional metal halide perovskites(MHPs)have attracted increased attention for radiation detection and imaging.Their detection efficiencies are almost comparable to three-dimensional(3D)perovskit...In recent years,two-dimensional metal halide perovskites(MHPs)have attracted increased attention for radiation detection and imaging.Their detection efficiencies are almost comparable to three-dimensional(3D)perovskites.Meanwhile,they demonstrate superior stability to 3D perovskites.The pursuit of high-quality,phase-pure and lead-free two-dimensional MHP materials and large-area fabrication capability for x-ray detectors are among the research hotspots.In this review,we first give a brief introduction of the crystallographic structure,optoelectronic characteristics and preparation methods of high-quality two-dimensional perovskites.In addition,we overview the general working principles of direct and indirect x-ray detection processes and the corresponding performance metrics from the perspective of detection and imaging.Furthermore,we provide a comprehensive discussion on the recent advances in 2D perovskite x-ray detectors and imaging devices.Finally,we pinpoint several major obstacles of 2D x-ray detectors that should be overcome in the near future.展开更多
In comparison to inorganic counterparts,organic semiconducting(OSC)crystalline films are promising for building large-area and flexible ionizing radiation detectors for X-ray imaging or dosimetry due to their tissue e...In comparison to inorganic counterparts,organic semiconducting(OSC)crystalline films are promising for building large-area and flexible ionizing radiation detectors for X-ray imaging or dosimetry due to their tissue equivalence,simple processing and large-scale production accessibility.Fabrication processes,how-ever,hinder the ability to generate aligned and large-area films with high carrier mobility.In this work,the space-confined melt process is used to produce highly orientated 4HCB(4-hydroxycyanobenzene)OSC films with a large area of 15×18 mm^(2).The out-of-plane direction of the 4HCB film is<001>,and the benzene rings are found to be extensively overlapped inside the in-plane direction,according to the XRD patterns.The film exhibits a high resistivity up to 1012cm,and high hole mobility of 10.62 cm^(2)V^(−1)s^(−1).Furthermore,the 4HCB(80μm-thick film)based X-ray detectors can achieve a sensitivity of 93μC Gy air^(−1) cm^(−2)and on/offratio of 157.The device also shows steady flexibility,with no degradation in detecting function after 100 cycles of bending.Finally,the proposed 4HCB film detectors demonstrated a high-resolution X-ray imaging capability.The imaging of several materials with sharp edges(copper and polytetrafluoroethylene)has been obtained.This work has developed a fast but efficient approach for producing large-area,highly oriented OSC films for high-performance X-ray detectors.展开更多
A diamond film with a size of 6×6×0.5 mm^3 is fabricated by electron-assisted chemical vapor deposition. Raman spectrum analysis, x-ray diffraction and scanning electron microscope images confirm the high pu...A diamond film with a size of 6×6×0.5 mm^3 is fabricated by electron-assisted chemical vapor deposition. Raman spectrum analysis, x-ray diffraction and scanning electron microscope images confirm the high purity and large grain size, which is larger than 300 μm. Its resistivity is higher than 10^12 W· cm. Interlaced-finger electrodes are imprinted onto the diamond film to develop an x-ray detector. Ohmic contact is confirmed by checking the linearity of its current–voltage curve. The dark current is lower than 0.1 n A under an electric field of 30 k V cm^-1. The time response is 220 ps. The sensitivity is about 125 m A W^-1 under a biasing voltage of 100 V.A good linear radiation dose rate is also confirmed. This diamond detector is used to measure x-ray on a Z-pinch, which has a double-layer 'nested tungsten wire array'. The pronounced peaks in the measured waveform clearly characterize the x-ray bursts, which proves the performance of this diamond detector.展开更多
Sensitive and reliable X-ray detectors are essential for medical radiography,industrial inspection and security screening.Lowering the radiation dose allows reduced health risks and increased frequency and fidelity of...Sensitive and reliable X-ray detectors are essential for medical radiography,industrial inspection and security screening.Lowering the radiation dose allows reduced health risks and increased frequency and fidelity of diagnostic technologies for earlier detection of disease and its recurrence.Three-dimensional(3 D)organic-inorganic hybrid lead halide perovskites are promising for direct X-ray detection-they show improved sensitivity compared to conventional X-ray detectors.However,their high and unstable dark current,caused by ion migration and high dark carrier concentration in the 3 D hybrid perovskites,limits their performance and long-term operation stability.Here we report ultrasensitive,stable X-ray detectors made using zero-dimensional(0 D)methylammonium bismuth iodide perovskite(MA3Bi2I9)single crystals.The 0 D crystal structure leads to a high activation energy(Ea)for ion migration(0.46 e V)and is also accompanied by a low dark carrier concentration(~10^6 cm^-3).The X-ray detectors exhibit sensitivity of 10,620μC Gy-1 air cm-2,a limit of detection(Lo D)of 0.62 nG yairs-1,and stable operation even under high applied biases;no deterioration in detection performance was observed following sensing of an integrated X-ray irradiation dose of^23,800 m Gyair,equivalent to>200,000 times the dose required for a single commercial X-ray chest radiograph.Regulating the ion migration channels and decreasing the dark carrier concentration in perovskites provide routes for stable and ultrasensitive X-ray detectors.展开更多
Perovskite materials have triggered a renewed interest in photovoltaic research in the recent years.They display crystal forms with 0D,1D and 2D,3D motifs,and several chemical forms,namely inorganic(titanates,rubidiat...Perovskite materials have triggered a renewed interest in photovoltaic research in the recent years.They display crystal forms with 0D,1D and 2D,3D motifs,and several chemical forms,namely inorganic(titanates,rubidiates,nobiates,tantalates etc.),organic/inorganic metal halides with single to multiple cations,and even organic polymer or quantum dot-infused hybrids.Each crystal type and chemical form are endowed with specific physicochemical,optical,electronic,and morphological properties.These unique properties render them suitable for targeted applications,namely photovoltaics,LEDs,photocatalysis/electrolysis/solar fuels/solar and Li-ion batteries,gas-sensors,ferroelectrics,capacitors,transistors and memristors,photodetectors,and lasers,for advanced quantum cryptography and outer space applications.At first,the crystal and material types,and physicochemical,morphological,and optoelectronic properties of perovskite materials are discussed.Particularly,we focus on those properties which cumulatively contribute to their application in the abovementioned fields.Simultaneously,a comprehensive discussion about the advances in each field is presented.Structure/property/application relationships with key advances demonstrate the versatility of perovskites in modern optoelectronic technologies.展开更多
A dilation X-ray detector(DIXD)based on time dilation and microchannel plate(MCP)gated technology has been reported.The DIXD passes a driving pulse along the transmission photocathode(PC)to obtain a dilated electron s...A dilation X-ray detector(DIXD)based on time dilation and microchannel plate(MCP)gated technology has been reported.The DIXD passes a driving pulse along the transmission photocathode(PC)to obtain a dilated electron signal and finally achieves a high time resolution of 12 ps.Furthermore,the waveform of the PC driving pulse can be obtained using the DIXD,and a DIXD oscillographic function can be obtained.An experiment is presented to demonstrate the DIXD oscilloscope.The waveform of the PC driving pulse from points t_(1) to t_(12) is achieved by the DIXD.The waveform agrees well with that measured by a high-speed oscilloscope with a difference of less than 6%.The maximum theoretical bandwidth of the DIXD oscilloscope is theoretically studied.The bandwidth is limited by the potential difference between the PC and mesh.When the potential difference is 3.4 kV,the theoretical limiting bandwidth is 1000 GHz.The bandwidth increases with an increase in the potential difference.展开更多
Metal halide perovskites have recently emerged as promising candidates for the next generation of X-ray detectors due to their excellent optoelectronic properties.Especially,two-dimensional(2D)perovskites afford many ...Metal halide perovskites have recently emerged as promising candidates for the next generation of X-ray detectors due to their excellent optoelectronic properties.Especially,two-dimensional(2D)perovskites afford many distinct properties,including remarkable structural diversity,high generation energy,and balanced large exciton binding energy.With the advantages of 2D materials and perovskites,it successfully reduces the decomposition and phase transition of perovskite and effectively suppresses ion migration.Meanwhile,the existence of a high hydrophobic spacer can block water molecules,thus making 2D perovskite obtain excellent stability.All of these advantages have attracted much attention in the field of X-ray detection.This review introduces the classification of 2D halide perovskites,summarizes the synthesis technology and performance characteristics of 2D perovskite X-ray direct detector,and briefly discusses the application of 2D perovskite in scintillators.Finally,this review also emphasizes the key challenges faced by 2D perovskite X-ray detectors in practical application and presents our views on its future development.展开更多
The efficient production of high-quality scintillators with long radioluminescence afterglow is crucial for high-performance X-ray luminescence extension imaging.However,scaling-up the synthesis of ligand-free scintil...The efficient production of high-quality scintillators with long radioluminescence afterglow is crucial for high-performance X-ray luminescence extension imaging.However,scaling-up the synthesis of ligand-free scintillators to fabricate large-area X-ray imaging screens for industrial applications remains a challenge.In this study,we report an efficient method to synthesize ligand-free,lanthanide-doped microscintillators by a one-pot reaction via the concentrated hydrothermal method.The as-synthesized microscintillators exhibit prolonged persistent radioluminescence for up to 30 days after X-ray exposure and remain high stability in air or water for more than 18 months without deterioration.Monte Carlo simulations indicate that the size effect is responsible for the excellent afterglow performance of the microscintillators.We employ these high-quality lanthanide-doped microscintillators to fabricate a large-area X-ray imaging detector using a blade-coating method,a spatial resolution of 24.9 lp/mm for X-ray imaging.Our study offers a solution for scaling-up the synthesis of low-cost microscintillators for practical applications.展开更多
Topmetal-M2 is a large-area pixel sensor chip fabricated using the GSMC 130 nm CMOS process in 2021.The pixel array of Topmetal-M2 consists of pixels of 400 rows×512 columns with a pixel pitch of 45μm×45μm...Topmetal-M2 is a large-area pixel sensor chip fabricated using the GSMC 130 nm CMOS process in 2021.The pixel array of Topmetal-M2 consists of pixels of 400 rows×512 columns with a pixel pitch of 45μm×45μm.The array is divided into 16 subarrays,with pixels of 400 rows×32 columns per subarray.Each pixel incorporates two charge sensors:a diode sensor and a Topmetal sensor.The in-pixel circuit primarily consists of a charge-sensitive amplifier for energy measurements,a discriminator with a peak-holding circuit,and a time-to-amplitude converter for time-of-arrival measurements.The pixel of Topmetal-M2 has a charge input range of~0-3 k e-,a voltage output range of~0-180 mV,and a charge-voltage conversion gain of~59.56μV∕e-.The average equivalent noise charge of Topmetal-M2,which includes the readout electronic system noise,is~43.45 e-.In the scanning mode,the time resolution of Topmetal-M2 is 1 LSB=1.25μs,and the precision is^()7.41μs.At an operating voltage of 1.5 V,Topmetal-M2 has a power consumption of~49 mW∕cm~2.In this article,we provide a comprehensive overview of the chip architecture,pixel working principles,and functional behavior of Topmetal-M2.Furthermore,we present the results of preliminary tests conducted on Topmetal-M2,namely,alpha-particle and soft X-ray tests.展开更多
Taking advantage of the excellent stability and photoelectric properties,two-dimensional(2D)organicinorganic halide perovskites have been widely researched and applied in optoelectronic and photovoltaic devices.The re...Taking advantage of the excellent stability and photoelectric properties,two-dimensional(2D)organicinorganic halide perovskites have been widely researched and applied in optoelectronic and photovoltaic devices.The remarkable properties are attributed to the unique quantum well structures by intercalating large organic ammonium space layers.In this review,we first summarize the crystal structures and growth methods of 2D halide perovskite crystals.Then,the distinctive optical characteristics and enhanced stability under high humidity,phase stability,suppressed ion migration,and high formation energy,are discussed in detail.Furthermore,we discuss orientation control in 2D perovskite films.The applications of 2D perovskites in solar cells,photo detectors and X-ray detectors are discussed in detail.Finally,we propose an outlook and perspectives to overcome the present challenges and broaden this new class of perovskite materials with other 2D nanomaterials.展开更多
Inorganic perovskite wafers with good stability and adjustable sizes are promising in X-ray detection but the high synthetic temperature is a hindrance.Herein,dimethyl sulfoxide(DMSO)is used to prepare the CsPbBr_(3)m...Inorganic perovskite wafers with good stability and adjustable sizes are promising in X-ray detection but the high synthetic temperature is a hindrance.Herein,dimethyl sulfoxide(DMSO)is used to prepare the CsPbBr_(3)micro-bricks powder at room temperature.The CsPbBr_(3)powder has a cubic shape with few crystal defects,small charge trap density,and high crystallinity.A trace amount of DMSO attaches to the surface of the CsPbBr_(3)micro-bricks via Pb-O bonding,forming the CsPbBr_(3)-DMSO adduct.During hot isostatic processing,the released DMSO vapor merges the CsPbBr_(3)micro-bricks,producing a compact and dense CsPbBr_(3)wafer with minimized grain boundaries and excellent charge transport properties.The CsPbBr_(3)wafer shows a large mobility-lifetime(μτ)product of 5.16×10^(-4)cm^(2)·V^(-1),high sensitivity of 14,430μC·Gyair^(-1)·cm^(-2),low detection limit of 564 nGyair·s^(-1),as well as robust stability in X-ray detection.The results reveal a novel strategy with immense practical potential pertaining to high-contrast X-ray detection.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
Copper-based metal halides have become important materials in the feld of X-ray and photodetection due to their excellent optical properties,good environmental stability and low toxicity.This review presents the progr...Copper-based metal halides have become important materials in the feld of X-ray and photodetection due to their excellent optical properties,good environmental stability and low toxicity.This review presents the progress of research on crystal structure/morphology,photophysics/optical properties and applications of copper-based metal halides.We also discuss the challenges of copper-based metal halides with a perspective of their future research directions.展开更多
Introduction Pixel detectors fabricated with the silicon-on-insulator(SOI)technology suffered from the digital pickup,due to the capacitive coupling between the sensing electrode and the in-pixel circuit.In order to t...Introduction Pixel detectors fabricated with the silicon-on-insulator(SOI)technology suffered from the digital pickup,due to the capacitive coupling between the sensing electrode and the in-pixel circuit.In order to tackle this issue,an advanced process called double SOI has been developed.A prototype chip CPIXTEG3b adopting this new process was designed and characterized.While optimization concerning the double-SOI design and testing of the single pixel were already presented in a separate publication,this paper focuses on its noise performance of the full matrix and X-ray detection utilizing a synchrotron photon beam.Methods Equivalent noise charge(ENC)of the full pixel matrix was measured with electrical pulse tests.The threshold dispersion was minimized by the DAC tuning in each individual pixel.As a photon-counting X-ray imager,noise count accumulated up to 1 h was measured.Detection efficiency was measured with a micro-focused beam as well as a flat field generated by the X-ray scattering on a glassy carbon at the KEK PF beam line 14A.Results The typical ENC is 52 e−and the sigma of threshold dispersion is 10 e−over the full matrix.A merit of“zero”noise count is also demonstrated,which is consistent with the low ENC.The prototype chip has been tested with microbeam and used to measure the beam profile to be with a full width of 50µm at 2.4%of the maximum height.Both sensor depletion and charge sharing between neighboring pixels have been carefully characterized,providing insights for further development.The homogeneity of response to X-ray photons has been demonstrated in the flat field test.This work has drawn a final conclusion to the solution of digital pickup issue and opened a promising prospect in low-noise and high-resolution X-ray imaging.展开更多
基金the China National Space Administration(CNSA)the Macao University of Science and Technology Foundation for their support of this paper。
文摘The solar X-ray detector(SXD)onboard the Macao Science Satellite-1B was designed to monitor solar flare bursts and to study the solar activity in the 25th solar cycle.The SXD includes two parts:a soft X-ray detection unit and a hard X-ray detection unit.Both the soft X-ray detection unit and the hard X-ray detection unit include two collimators,two X-ray detectors(a silicon drift detector and a cadmium-zinc-telluride detector),and a processing circuit.Compared with similar instruments,the energy range of the SXD is wider(1–600 ke V)and the energy resolution is better(150 e V at 5.9 ke V,12%at 59.5 ke V,and 3%at 662 keV).
基金supported by the China Natural Science Fund (No.52171253)Natural Science Foundation of Sichuan (No.2022NSFSC0949)。
文摘X-ray imaging technologies such as digital radiography(DR),is an important aspect of modern non-destructive testing and medical diagnosis.Innovative flexible X-ray detector technologies have recently been proposed and are now receiving increasing attention owing to their superior material flexibility compared with traditional flat-panel detectors.This work aims to study these innovative flexible X-ray detectors in terms of their effectiveness in DR imaging,such as detection efficiency and spatial resolution.To achieve this goal,first,a Monte Carlo model was developed and calibrated to an in-lab 150 kV DR imaging system containing a flat-panel X-ray detector.Second,the validated model was updated with various types of flexible X-ray detectors to assess their performance in nearly realistic conditions.Key parameters such as the detection efficiency pertaining to the crystal material and thickness were studied and analyzed across a broader energy range up to 662 keV.Finally,the imaging performance of the different detectors was evaluated and compared to that of the flat-panel detector in the 150 kV DR imaging system.The results show that the flexible detectors such as the CsPbBr3crystal detector deliver promising performance in X-ray imaging and can be applied to a wider range of application scenarios,especially those requiring accurate detection at challenging angles.
基金supported by the National Natural Science Foundation of China(22279083)Natural Science Foundation of Guangdong Province(2019A1515010783)+1 种基金Guangzhou Science and Technology Planning Project(202102010443)Songshan Lake Materials Laboratory.
文摘In recent years,two-dimensional metal halide perovskites(MHPs)have attracted increased attention for radiation detection and imaging.Their detection efficiencies are almost comparable to three-dimensional(3D)perovskites.Meanwhile,they demonstrate superior stability to 3D perovskites.The pursuit of high-quality,phase-pure and lead-free two-dimensional MHP materials and large-area fabrication capability for x-ray detectors are among the research hotspots.In this review,we first give a brief introduction of the crystallographic structure,optoelectronic characteristics and preparation methods of high-quality two-dimensional perovskites.In addition,we overview the general working principles of direct and indirect x-ray detection processes and the corresponding performance metrics from the perspective of detection and imaging.Furthermore,we provide a comprehensive discussion on the recent advances in 2D perovskite x-ray detectors and imaging devices.Finally,we pinpoint several major obstacles of 2D x-ray detectors that should be overcome in the near future.
基金This work was supported by the National Natural Science Foundations of China(Nos.U2032170,51872228,62104194 and 51802262)The project was also supported by the Fundamental Research Funds for the Central University(3102020QD0408 and D5000210906)+1 种基金the Natural Science Foundation of Shaanxi Province(2020JC-12)the Research Fund of the State Key Laboratory of Solidification Processing(NPU),China(No.2022-TS-07).
文摘In comparison to inorganic counterparts,organic semiconducting(OSC)crystalline films are promising for building large-area and flexible ionizing radiation detectors for X-ray imaging or dosimetry due to their tissue equivalence,simple processing and large-scale production accessibility.Fabrication processes,how-ever,hinder the ability to generate aligned and large-area films with high carrier mobility.In this work,the space-confined melt process is used to produce highly orientated 4HCB(4-hydroxycyanobenzene)OSC films with a large area of 15×18 mm^(2).The out-of-plane direction of the 4HCB film is<001>,and the benzene rings are found to be extensively overlapped inside the in-plane direction,according to the XRD patterns.The film exhibits a high resistivity up to 1012cm,and high hole mobility of 10.62 cm^(2)V^(−1)s^(−1).Furthermore,the 4HCB(80μm-thick film)based X-ray detectors can achieve a sensitivity of 93μC Gy air^(−1) cm^(−2)and on/offratio of 157.The device also shows steady flexibility,with no degradation in detecting function after 100 cycles of bending.Finally,the proposed 4HCB film detectors demonstrated a high-resolution X-ray imaging capability.The imaging of several materials with sharp edges(copper and polytetrafluoroethylene)has been obtained.This work has developed a fast but efficient approach for producing large-area,highly oriented OSC films for high-performance X-ray detectors.
基金supported by the National Key R&D Program of China(Grant No.2017YFE0301300)the Hunan Provincial Innovation Foundation for Postgraduate(Grant No.CX2018B588)。
文摘A diamond film with a size of 6×6×0.5 mm^3 is fabricated by electron-assisted chemical vapor deposition. Raman spectrum analysis, x-ray diffraction and scanning electron microscope images confirm the high purity and large grain size, which is larger than 300 μm. Its resistivity is higher than 10^12 W· cm. Interlaced-finger electrodes are imprinted onto the diamond film to develop an x-ray detector. Ohmic contact is confirmed by checking the linearity of its current–voltage curve. The dark current is lower than 0.1 n A under an electric field of 30 k V cm^-1. The time response is 220 ps. The sensitivity is about 125 m A W^-1 under a biasing voltage of 100 V.A good linear radiation dose rate is also confirmed. This diamond detector is used to measure x-ray on a Z-pinch, which has a double-layer 'nested tungsten wire array'. The pronounced peaks in the measured waveform clearly characterize the x-ray bursts, which proves the performance of this diamond detector.
基金supported by the National Natural Science Foundation of China(Grant nos.21773218,61974063)the Sichuan Province(Grant no.2018JY0206)the China Academy of Engineering Physics(Grant no.YZJJLX2018007)。
文摘Sensitive and reliable X-ray detectors are essential for medical radiography,industrial inspection and security screening.Lowering the radiation dose allows reduced health risks and increased frequency and fidelity of diagnostic technologies for earlier detection of disease and its recurrence.Three-dimensional(3 D)organic-inorganic hybrid lead halide perovskites are promising for direct X-ray detection-they show improved sensitivity compared to conventional X-ray detectors.However,their high and unstable dark current,caused by ion migration and high dark carrier concentration in the 3 D hybrid perovskites,limits their performance and long-term operation stability.Here we report ultrasensitive,stable X-ray detectors made using zero-dimensional(0 D)methylammonium bismuth iodide perovskite(MA3Bi2I9)single crystals.The 0 D crystal structure leads to a high activation energy(Ea)for ion migration(0.46 e V)and is also accompanied by a low dark carrier concentration(~10^6 cm^-3).The X-ray detectors exhibit sensitivity of 10,620μC Gy-1 air cm-2,a limit of detection(Lo D)of 0.62 nG yairs-1,and stable operation even under high applied biases;no deterioration in detection performance was observed following sensing of an integrated X-ray irradiation dose of^23,800 m Gyair,equivalent to>200,000 times the dose required for a single commercial X-ray chest radiograph.Regulating the ion migration channels and decreasing the dark carrier concentration in perovskites provide routes for stable and ultrasensitive X-ray detectors.
文摘Perovskite materials have triggered a renewed interest in photovoltaic research in the recent years.They display crystal forms with 0D,1D and 2D,3D motifs,and several chemical forms,namely inorganic(titanates,rubidiates,nobiates,tantalates etc.),organic/inorganic metal halides with single to multiple cations,and even organic polymer or quantum dot-infused hybrids.Each crystal type and chemical form are endowed with specific physicochemical,optical,electronic,and morphological properties.These unique properties render them suitable for targeted applications,namely photovoltaics,LEDs,photocatalysis/electrolysis/solar fuels/solar and Li-ion batteries,gas-sensors,ferroelectrics,capacitors,transistors and memristors,photodetectors,and lasers,for advanced quantum cryptography and outer space applications.At first,the crystal and material types,and physicochemical,morphological,and optoelectronic properties of perovskite materials are discussed.Particularly,we focus on those properties which cumulatively contribute to their application in the abovementioned fields.Simultaneously,a comprehensive discussion about the advances in each field is presented.Structure/property/application relationships with key advances demonstrate the versatility of perovskites in modern optoelectronic technologies.
基金supported by the Program for National Natural Science Foundation of China(NSFC)(11775147)Guangdong Basic and Applied Basic Research Foundation(Nos.2019A1515011474 and2019A1515110130)Shenzhen Science and Technology Program(Nos.JCYJ20210324095007020,JCYJ20200109105201936,and JCYJ20190808115605501)。
文摘A dilation X-ray detector(DIXD)based on time dilation and microchannel plate(MCP)gated technology has been reported.The DIXD passes a driving pulse along the transmission photocathode(PC)to obtain a dilated electron signal and finally achieves a high time resolution of 12 ps.Furthermore,the waveform of the PC driving pulse can be obtained using the DIXD,and a DIXD oscillographic function can be obtained.An experiment is presented to demonstrate the DIXD oscilloscope.The waveform of the PC driving pulse from points t_(1) to t_(12) is achieved by the DIXD.The waveform agrees well with that measured by a high-speed oscilloscope with a difference of less than 6%.The maximum theoretical bandwidth of the DIXD oscilloscope is theoretically studied.The bandwidth is limited by the potential difference between the PC and mesh.When the potential difference is 3.4 kV,the theoretical limiting bandwidth is 1000 GHz.The bandwidth increases with an increase in the potential difference.
基金This work was funded by the National Natural Science Foundation of China(22279049 and 12247101)the Fundamental Research Funds for the Central Universities(lzujbky-2021-it31,lzujbky-2021-ct15 and lzujbky-2021-sp69)+1 种基金the calculation work was supported by Supercomputing Center of Lanzhou Universitythe Gansu Province Outstanding Doctoral Student Program(22JR5RA435).
文摘Metal halide perovskites have recently emerged as promising candidates for the next generation of X-ray detectors due to their excellent optoelectronic properties.Especially,two-dimensional(2D)perovskites afford many distinct properties,including remarkable structural diversity,high generation energy,and balanced large exciton binding energy.With the advantages of 2D materials and perovskites,it successfully reduces the decomposition and phase transition of perovskite and effectively suppresses ion migration.Meanwhile,the existence of a high hydrophobic spacer can block water molecules,thus making 2D perovskite obtain excellent stability.All of these advantages have attracted much attention in the field of X-ray detection.This review introduces the classification of 2D halide perovskites,summarizes the synthesis technology and performance characteristics of 2D perovskite X-ray direct detector,and briefly discusses the application of 2D perovskite in scintillators.Finally,this review also emphasizes the key challenges faced by 2D perovskite X-ray detectors in practical application and presents our views on its future development.
基金the National Key Research&Development Program of China(Nos.2020YFA0709900,2020YFA0210800)the National Natural Science Foundation of China(Nos.22027805,62134003,22104016)+1 种基金the Natural Science Foundation of Fujian Province(Nos.2022J01709,2023J01384)the Major Project of Science and Technology of Fujian Province(No.2020HZ06006)。
文摘The efficient production of high-quality scintillators with long radioluminescence afterglow is crucial for high-performance X-ray luminescence extension imaging.However,scaling-up the synthesis of ligand-free scintillators to fabricate large-area X-ray imaging screens for industrial applications remains a challenge.In this study,we report an efficient method to synthesize ligand-free,lanthanide-doped microscintillators by a one-pot reaction via the concentrated hydrothermal method.The as-synthesized microscintillators exhibit prolonged persistent radioluminescence for up to 30 days after X-ray exposure and remain high stability in air or water for more than 18 months without deterioration.Monte Carlo simulations indicate that the size effect is responsible for the excellent afterglow performance of the microscintillators.We employ these high-quality lanthanide-doped microscintillators to fabricate a large-area X-ray imaging detector using a blade-coating method,a spatial resolution of 24.9 lp/mm for X-ray imaging.Our study offers a solution for scaling-up the synthesis of low-cost microscintillators for practical applications.
基金supported by the National Key Research and Development Program of China(No.2020YFE0202002)the National Natural Science Foundation of China(Nos.11875146 and U1932143)。
文摘Topmetal-M2 is a large-area pixel sensor chip fabricated using the GSMC 130 nm CMOS process in 2021.The pixel array of Topmetal-M2 consists of pixels of 400 rows×512 columns with a pixel pitch of 45μm×45μm.The array is divided into 16 subarrays,with pixels of 400 rows×32 columns per subarray.Each pixel incorporates two charge sensors:a diode sensor and a Topmetal sensor.The in-pixel circuit primarily consists of a charge-sensitive amplifier for energy measurements,a discriminator with a peak-holding circuit,and a time-to-amplitude converter for time-of-arrival measurements.The pixel of Topmetal-M2 has a charge input range of~0-3 k e-,a voltage output range of~0-180 mV,and a charge-voltage conversion gain of~59.56μV∕e-.The average equivalent noise charge of Topmetal-M2,which includes the readout electronic system noise,is~43.45 e-.In the scanning mode,the time resolution of Topmetal-M2 is 1 LSB=1.25μs,and the precision is^()7.41μs.At an operating voltage of 1.5 V,Topmetal-M2 has a power consumption of~49 mW∕cm~2.In this article,we provide a comprehensive overview of the chip architecture,pixel working principles,and functional behavior of Topmetal-M2.Furthermore,we present the results of preliminary tests conducted on Topmetal-M2,namely,alpha-particle and soft X-ray tests.
基金funded by the National Key Research and Development Program of China(2017YFA0204800)the National Natural Science Foundation of China(91733301/61674098/51901190)+3 种基金the DNL Cooperation Fund CAS(DNL180311)the 111 Project(B14041)the Changjiang Scholars,Innovative Research Team(IRT_14R33)the China Postdoctoral Science Foundation(2020M673336)。
文摘Taking advantage of the excellent stability and photoelectric properties,two-dimensional(2D)organicinorganic halide perovskites have been widely researched and applied in optoelectronic and photovoltaic devices.The remarkable properties are attributed to the unique quantum well structures by intercalating large organic ammonium space layers.In this review,we first summarize the crystal structures and growth methods of 2D halide perovskite crystals.Then,the distinctive optical characteristics and enhanced stability under high humidity,phase stability,suppressed ion migration,and high formation energy,are discussed in detail.Furthermore,we discuss orientation control in 2D perovskite films.The applications of 2D perovskites in solar cells,photo detectors and X-ray detectors are discussed in detail.Finally,we propose an outlook and perspectives to overcome the present challenges and broaden this new class of perovskite materials with other 2D nanomaterials.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.21975280,62004091,and 12235006)the Shenzhen Excellent Science and Technology Innovation Talent Training Project-Outstanding Youth Project(No.RCJC20200714114435061)+5 种基金the Shenzhen Basic Research Program(No.JCYJ20200109115212546)the Chinese Academy of Sciences Special Research Assistant Project(Nos.Y95909 and E15907)the Chinese Academy of Sciences Excellent Youth Innovation Fund grade B(No.E2G0161001)the Youth Innovation Promotion Association Chinese Academy of Sciences(No.2020354)the Hong Kong ITC(Innovation and Technology Commission)ITF(Innovation and Technology Fund)(Nos.GHP/149/20SZ and CityU 9440296)the City University of Hong Kong Donation Research Grant(DON-RMG No.9229021).
文摘Inorganic perovskite wafers with good stability and adjustable sizes are promising in X-ray detection but the high synthetic temperature is a hindrance.Herein,dimethyl sulfoxide(DMSO)is used to prepare the CsPbBr_(3)micro-bricks powder at room temperature.The CsPbBr_(3)powder has a cubic shape with few crystal defects,small charge trap density,and high crystallinity.A trace amount of DMSO attaches to the surface of the CsPbBr_(3)micro-bricks via Pb-O bonding,forming the CsPbBr_(3)-DMSO adduct.During hot isostatic processing,the released DMSO vapor merges the CsPbBr_(3)micro-bricks,producing a compact and dense CsPbBr_(3)wafer with minimized grain boundaries and excellent charge transport properties.The CsPbBr_(3)wafer shows a large mobility-lifetime(μτ)product of 5.16×10^(-4)cm^(2)·V^(-1),high sensitivity of 14,430μC·Gyair^(-1)·cm^(-2),low detection limit of 564 nGyair·s^(-1),as well as robust stability in X-ray detection.The results reveal a novel strategy with immense practical potential pertaining to high-contrast X-ray detection.
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funded by the National Natural Science Foundation of China(Grant Nos.22279049 and 52073131)the Fundamental Research Funds for the Central Universities(Nos.lzujbky-2021-ct15 and lzujbky-2021-sp69).
文摘Copper-based metal halides have become important materials in the feld of X-ray and photodetection due to their excellent optical properties,good environmental stability and low toxicity.This review presents the progress of research on crystal structure/morphology,photophysics/optical properties and applications of copper-based metal halides.We also discuss the challenges of copper-based metal halides with a perspective of their future research directions.
基金This work is supported by the National Nature Science Foundation of China,Grant Nos.11375226 and 11575220.
文摘Introduction Pixel detectors fabricated with the silicon-on-insulator(SOI)technology suffered from the digital pickup,due to the capacitive coupling between the sensing electrode and the in-pixel circuit.In order to tackle this issue,an advanced process called double SOI has been developed.A prototype chip CPIXTEG3b adopting this new process was designed and characterized.While optimization concerning the double-SOI design and testing of the single pixel were already presented in a separate publication,this paper focuses on its noise performance of the full matrix and X-ray detection utilizing a synchrotron photon beam.Methods Equivalent noise charge(ENC)of the full pixel matrix was measured with electrical pulse tests.The threshold dispersion was minimized by the DAC tuning in each individual pixel.As a photon-counting X-ray imager,noise count accumulated up to 1 h was measured.Detection efficiency was measured with a micro-focused beam as well as a flat field generated by the X-ray scattering on a glassy carbon at the KEK PF beam line 14A.Results The typical ENC is 52 e−and the sigma of threshold dispersion is 10 e−over the full matrix.A merit of“zero”noise count is also demonstrated,which is consistent with the low ENC.The prototype chip has been tested with microbeam and used to measure the beam profile to be with a full width of 50µm at 2.4%of the maximum height.Both sensor depletion and charge sharing between neighboring pixels have been carefully characterized,providing insights for further development.The homogeneity of response to X-ray photons has been demonstrated in the flat field test.This work has drawn a final conclusion to the solution of digital pickup issue and opened a promising prospect in low-noise and high-resolution X-ray imaging.
