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
Lead halide perovskite (LHP) nanocrystals have been intensely studied as photocatalysts for artificial photosynthesis in recent years.However,the toxicity of lead in LHP seriously limits their potential for widespread...Lead halide perovskite (LHP) nanocrystals have been intensely studied as photocatalysts for artificial photosynthesis in recent years.However,the toxicity of lead in LHP seriously limits their potential for widespread applications.Herein,we first present the synthesis of 2D lead-free halide perovskite (Cs_(3)Bi_(2)I_(9)) nanosheets with self-template-oriented method,in which BiOI/Bi_(2)O_(2) nanosheets were used as the template and Bi ion source simultaneously.Through facile electrostatic self-assembly strategy,a Z-scheme heterojunction composed of Cs_(3)Bi_(2)I_(9)nanosheets and CeO_(2) nanosheets (Cs_(3)Bi_(2)I_(9)/CeO_(2)-3:1) was constructed as photocatalyst for the photo-reduction of CO_(2) coupled with the oxidation of H_(2)O.Due to the matching energy levels and the close interfacial contact between Cs_(3)Bi_(2)I_(9)and CeO_(2) nanosheets,the separation efficiency of the photogenerated carriers in Cs_(3)Bi_(2)I_(9)/CeO_(2)-3:1 composite was significantly improved.Consequently,the environment-friendly halide perovskite heterojunction Cs_(3)Bi_(2)I_(9)/CeO_(2)-3:1presents impressive photocatalytic activity for the reduction of CO_(2)to CH_(4)and CO with an electron consumption yield of 877.04μmol g^(-1),which is over 7 and 15 times higher than those of pristine Cs_(3)Bi_(2)I_(9)and CeO_(2)nanosheets,exceeding the yield of other reported bismuth-based perovskite for photocatalytic CO_(2)reduction.展开更多
The g-C_(3)N_(4)/BiOI/CdS double Z-scheme heterojunction photocatalyst with I_(3)^(-)/I^(-) redox pairs is prepared using simple calcination,solvothermal,and solution chemical deposition methods.The photocatalyst comp...The g-C_(3)N_(4)/BiOI/CdS double Z-scheme heterojunction photocatalyst with I_(3)^(-)/I^(-) redox pairs is prepared using simple calcination,solvothermal,and solution chemical deposition methods.The photocatalyst comprised mesoporous,thin g-C_(3)N_(4) nanosheets loaded on flower-like microspheres of BiOI with CdS quantum dots.The g-C_(3)N_(4)/BiOI/CdS double Z-scheme heterojunction has abundant active sites and in situ redox I_(3)^(-)/I^(-) mediators and shows quantum size effects,which are all conducive to enhancing the separation of photoinduced charges and increasing the photocatalytic degradation efficiency for bisphenol A,a model pollutant.Specifically,the heterojunction photocatalyst achieves a photocatalytic degradation efficiency for bisphenol A of 98.62%in 120 min and photocatalytic hydrogen production of 863.44 mmol h^(-1) g^(-1) on exposure to visible light.The excellent visible-light photocatalytic performance is as a result of the Z-scheme heterojunction,which extends absorption to the visible light region,as well as the I_(3)^(-)/I^(-) pairs,which accelerate photoinduced charge carrier transfer and separation,thus dramatically boosting the photocatalytic performance.In addition,the key role of the charge transfer across the indirect Z-scheme heterojunction has been elucidated and the transfer mechanism is confirmed based on the detection of intermediate I_(3)^(-)ions.Thus,this study provides guidelines for the design of indirect Z-scheme heterojunction photocatalysts.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financially supported by the Natural Science Foundation of Tianjin City (17JCJQJC43800, 19JCQNJC05500)the National Key R&D Program of China (2017YFA0700104)+1 种基金NSFC (21931007)the 111 Project of China (D17003)。
文摘Lead halide perovskite (LHP) nanocrystals have been intensely studied as photocatalysts for artificial photosynthesis in recent years.However,the toxicity of lead in LHP seriously limits their potential for widespread applications.Herein,we first present the synthesis of 2D lead-free halide perovskite (Cs_(3)Bi_(2)I_(9)) nanosheets with self-template-oriented method,in which BiOI/Bi_(2)O_(2) nanosheets were used as the template and Bi ion source simultaneously.Through facile electrostatic self-assembly strategy,a Z-scheme heterojunction composed of Cs_(3)Bi_(2)I_(9)nanosheets and CeO_(2) nanosheets (Cs_(3)Bi_(2)I_(9)/CeO_(2)-3:1) was constructed as photocatalyst for the photo-reduction of CO_(2) coupled with the oxidation of H_(2)O.Due to the matching energy levels and the close interfacial contact between Cs_(3)Bi_(2)I_(9)and CeO_(2) nanosheets,the separation efficiency of the photogenerated carriers in Cs_(3)Bi_(2)I_(9)/CeO_(2)-3:1 composite was significantly improved.Consequently,the environment-friendly halide perovskite heterojunction Cs_(3)Bi_(2)I_(9)/CeO_(2)-3:1presents impressive photocatalytic activity for the reduction of CO_(2)to CH_(4)and CO with an electron consumption yield of 877.04μmol g^(-1),which is over 7 and 15 times higher than those of pristine Cs_(3)Bi_(2)I_(9)and CeO_(2)nanosheets,exceeding the yield of other reported bismuth-based perovskite for photocatalytic CO_(2)reduction.
基金support of this work by the National Natural Science Foundation of China(51869006)Jiangxi Natural Science Foundation of China(20171BAB216050)Water Science and Technology Fund of Jiangxi Province in China(KT201702).
文摘The g-C_(3)N_(4)/BiOI/CdS double Z-scheme heterojunction photocatalyst with I_(3)^(-)/I^(-) redox pairs is prepared using simple calcination,solvothermal,and solution chemical deposition methods.The photocatalyst comprised mesoporous,thin g-C_(3)N_(4) nanosheets loaded on flower-like microspheres of BiOI with CdS quantum dots.The g-C_(3)N_(4)/BiOI/CdS double Z-scheme heterojunction has abundant active sites and in situ redox I_(3)^(-)/I^(-) mediators and shows quantum size effects,which are all conducive to enhancing the separation of photoinduced charges and increasing the photocatalytic degradation efficiency for bisphenol A,a model pollutant.Specifically,the heterojunction photocatalyst achieves a photocatalytic degradation efficiency for bisphenol A of 98.62%in 120 min and photocatalytic hydrogen production of 863.44 mmol h^(-1) g^(-1) on exposure to visible light.The excellent visible-light photocatalytic performance is as a result of the Z-scheme heterojunction,which extends absorption to the visible light region,as well as the I_(3)^(-)/I^(-) pairs,which accelerate photoinduced charge carrier transfer and separation,thus dramatically boosting the photocatalytic performance.In addition,the key role of the charge transfer across the indirect Z-scheme heterojunction has been elucidated and the transfer mechanism is confirmed based on the detection of intermediate I_(3)^(-)ions.Thus,this study provides guidelines for the design of indirect Z-scheme heterojunction photocatalysts.
