Low-dimensional halide perovskites have become the most promising candidates for X-ray imaging,yet the issues of the poor chemical stability of hybrid halide perovskite,the high poisonousness of lead halides and the r...Low-dimensional halide perovskites have become the most promising candidates for X-ray imaging,yet the issues of the poor chemical stability of hybrid halide perovskite,the high poisonousness of lead halides and the relatively low detectivity of the lead-free halide perovskites which seriously restrain its commercialization.Here,we developed a solution inverse temperature crystal growth(ITCG)method to bring-up high quality Cs_(3)Cu_(2)I_(5)crystals with large size of centimeter order,in which the oleic acid(OA)is introduced as an antioxidative ligand to inhibit the oxidation of cuprous ions effieiently,as well as to decelerate the crystallization rate remarkalby.Based on these fine crystals,the vapor deposition technique is empolyed to prepare high quality Cs_(3)Cu_(2)I_(5)films for efficient X-ray imaging.Smooth surface morphology,high light yields and short decay time endow the Cs_(3)Cu_(2)I_(5)films with strong radioluminescence,high resolution(12 lp/mm),low detection limits(53 nGyair/s)and desirable stability.Subsequently,the Cs_(3)Cu_(2)I_(5)films have been applied to the practical radiography which exhibit superior X-ray imaging performance.Our work provides a paradigm to fabricate nonpoisonous and chemically stable inorganic halide perovskite for X-ray imaging.展开更多
Multicolor fluorescence of mixed halide perovskites enormously enables their applications in photonics and optoelectronics.However,it remains an arduous task to obtain multicolor emissions from perovskites containing ...Multicolor fluorescence of mixed halide perovskites enormously enables their applications in photonics and optoelectronics.However,it remains an arduous task to obtain multicolor emissions from perovskites containing single halogen to avoid phase segregation.Herein,a fluorescent composite containing Eu-based metal-organic frameworks(MOFs),OD Cs PbBre,and 3D CsPbBrs is synthesized.Under excitations at 365 nm and 254nm,the pristine composite emits blue(B)and red(R)fluorescence,which are ascribed to radiative defects within CsPbBr and 5Do→7F,transitions of Eu^(3+),respectively.Interestingly,after light soaking in the ambient environment,the blue fluorescence gradually converts into green(G)emission due to the defect repairing and 0D-3D phase conversion.This permanent and unique photochromic effect enables anticounterfeiting and microsteganography with increased security through a micropatterning technique.Moreover,the RGB luminescence is highly stable after encapsulation by a transparent polymer layer.Thus,trichromatic light-emitting modules are fabricated by using the fluorescent composites as color-converting layers,which almost fully cover the standard color gamut.Therefore,this work innovates a strategy for construction of tunable multicolor luminescence by manipulating the radiative defects and structural dimensionality.展开更多
Halide perovskites,such as methylammonium lead halide perovskites(MAPbX3,X=I,Br,and Cl),are emerging as promising candidates for a wide range of optoelectronic applications,including solar cells,light-emitting diodes,...Halide perovskites,such as methylammonium lead halide perovskites(MAPbX3,X=I,Br,and Cl),are emerging as promising candidates for a wide range of optoelectronic applications,including solar cells,light-emitting diodes,and photodetectors,due to their superior optoelectronic properties.All-inorganic lead halide perovskites CsPbX3 are attracting a lot of attention because replacing the organic cations with Cs+enhances the stability,and its halide-mixing derivatives offer broad bandgap tunability covering nearly the entire visible spectrum.However,there is evidence suggesting that the optical properties of mixed-halide perovskites are influenced by phase segregation under external stimuli,especially illumination,which may negatively impact the performance of optoelectronic devices.It is reported that the mixed-halide perovskites in forms of thin films and nanocrystals are segregated into a low-bandgap I-rich phase and a high-bandgap Br-rich phase.Herein,we present a critical review on the synthesis and basic properties of all-inorganic perovskites,phase-segregation phenomena,plausible mechanisms,and methods to mitigate phase segregation,providing insights on advancing mixed-halide perovskite optoelectronics with reliable performance.展开更多
A homogeneous layer of Bi_2O_3-Bi_(14)WO_(24) composite(BWO/Bi_2O_3) thin film was fabricated using a combination of electrodeposition and thermal treatment. The evenly distributed Bi14 WO24 component within the Bi_2O...A homogeneous layer of Bi_2O_3-Bi_(14)WO_(24) composite(BWO/Bi_2O_3) thin film was fabricated using a combination of electrodeposition and thermal treatment. The evenly distributed Bi14 WO24 component within the Bi_2O_3 layer was found to be important in stabilising the photoelectrochemical performances of Bi_2O_3 photoanode by promoting the photoelectron transport. The unmodified Bi_2O_3 suffered from severe photocorrosion as proven by X-ray diffraction(XRD) and inductively coupled plasma(ICP) analyses while the composite thin film was active without noticeable activity decay for at least 3 h of illumination. This strategy might be applicable to other photocatalysts with stability issues.展开更多
基金the financially support of the National Natural Science Foundation of China(12164051)the Joint Foundation of Provincial Science and Technology Department-Double First-class Construction of Yunnan University(2019FY003016)+4 种基金the Young Top Talent Project of Yunnan Province(YNWR-QNBJ-2018-229)the financially support by Yunnan Major Scientific and Technological Projects(202202AG050016)Advanced Analysis and Measurement Center of Yunnan University for the sample characterization service and the Postgraduate Research and Innovation Foundation of Yunnan University(2021Y036)the financially support of the National Natural Science Foundation of China(62064013)the Application Basic Research Project of Yunnan Province[2019FB130]。
文摘Low-dimensional halide perovskites have become the most promising candidates for X-ray imaging,yet the issues of the poor chemical stability of hybrid halide perovskite,the high poisonousness of lead halides and the relatively low detectivity of the lead-free halide perovskites which seriously restrain its commercialization.Here,we developed a solution inverse temperature crystal growth(ITCG)method to bring-up high quality Cs_(3)Cu_(2)I_(5)crystals with large size of centimeter order,in which the oleic acid(OA)is introduced as an antioxidative ligand to inhibit the oxidation of cuprous ions effieiently,as well as to decelerate the crystallization rate remarkalby.Based on these fine crystals,the vapor deposition technique is empolyed to prepare high quality Cs_(3)Cu_(2)I_(5)films for efficient X-ray imaging.Smooth surface morphology,high light yields and short decay time endow the Cs_(3)Cu_(2)I_(5)films with strong radioluminescence,high resolution(12 lp/mm),low detection limits(53 nGyair/s)and desirable stability.Subsequently,the Cs_(3)Cu_(2)I_(5)films have been applied to the practical radiography which exhibit superior X-ray imaging performance.Our work provides a paradigm to fabricate nonpoisonous and chemically stable inorganic halide perovskite for X-ray imaging.
基金supported by the Natural Science Foundation of Shandong Province(ZR2021YQ32)the Taishan Scholars Program of Shandong Province(tsqn201909117)+1 种基金support was given by the National Natural Science Foundation of China(6190i222,21802074,and 11604155)Natural Science Foundation of Jiangsu Province(BK20190697).
文摘Multicolor fluorescence of mixed halide perovskites enormously enables their applications in photonics and optoelectronics.However,it remains an arduous task to obtain multicolor emissions from perovskites containing single halogen to avoid phase segregation.Herein,a fluorescent composite containing Eu-based metal-organic frameworks(MOFs),OD Cs PbBre,and 3D CsPbBrs is synthesized.Under excitations at 365 nm and 254nm,the pristine composite emits blue(B)and red(R)fluorescence,which are ascribed to radiative defects within CsPbBr and 5Do→7F,transitions of Eu^(3+),respectively.Interestingly,after light soaking in the ambient environment,the blue fluorescence gradually converts into green(G)emission due to the defect repairing and 0D-3D phase conversion.This permanent and unique photochromic effect enables anticounterfeiting and microsteganography with increased security through a micropatterning technique.Moreover,the RGB luminescence is highly stable after encapsulation by a transparent polymer layer.Thus,trichromatic light-emitting modules are fabricated by using the fluorescent composites as color-converting layers,which almost fully cover the standard color gamut.Therefore,this work innovates a strategy for construction of tunable multicolor luminescence by manipulating the radiative defects and structural dimensionality.
基金Australian Research Council(DP190103316)UNSW SHARP Project(RG163043)+1 种基金US Office of Naval Research(N00014-18-1-2408)US National Science Foundation(CMMI-1930809).
文摘Halide perovskites,such as methylammonium lead halide perovskites(MAPbX3,X=I,Br,and Cl),are emerging as promising candidates for a wide range of optoelectronic applications,including solar cells,light-emitting diodes,and photodetectors,due to their superior optoelectronic properties.All-inorganic lead halide perovskites CsPbX3 are attracting a lot of attention because replacing the organic cations with Cs+enhances the stability,and its halide-mixing derivatives offer broad bandgap tunability covering nearly the entire visible spectrum.However,there is evidence suggesting that the optical properties of mixed-halide perovskites are influenced by phase segregation under external stimuli,especially illumination,which may negatively impact the performance of optoelectronic devices.It is reported that the mixed-halide perovskites in forms of thin films and nanocrystals are segregated into a low-bandgap I-rich phase and a high-bandgap Br-rich phase.Herein,we present a critical review on the synthesis and basic properties of all-inorganic perovskites,phase-segregation phenomena,plausible mechanisms,and methods to mitigate phase segregation,providing insights on advancing mixed-halide perovskite optoelectronics with reliable performance.
基金the National Natural Science Foundation of China(51802241 and 91963209)the Fundamental Research Funds for the Central Universities(WUT:2019IVB055 and 2019IVA066)+1 种基金ARC Discovery Grant DP150104483,ARC Centre of Excellence in Exciton Science(CE170100026)the Australian Government through the Australian Renewable Energy Agency(ARENA).
基金supported by the Australian Research Council under the Laureate Fellowship Scheme(FL140100081)
文摘A homogeneous layer of Bi_2O_3-Bi_(14)WO_(24) composite(BWO/Bi_2O_3) thin film was fabricated using a combination of electrodeposition and thermal treatment. The evenly distributed Bi14 WO24 component within the Bi_2O_3 layer was found to be important in stabilising the photoelectrochemical performances of Bi_2O_3 photoanode by promoting the photoelectron transport. The unmodified Bi_2O_3 suffered from severe photocorrosion as proven by X-ray diffraction(XRD) and inductively coupled plasma(ICP) analyses while the composite thin film was active without noticeable activity decay for at least 3 h of illumination. This strategy might be applicable to other photocatalysts with stability issues.
