A heightened understanding of nucleation and growth mechanisms is paramount if effective solution processing of organic-inorganic perovskite thin-films for optoelectronic applications is to be achieved. Many fabri- ca...A heightened understanding of nucleation and growth mechanisms is paramount if effective solution processing of organic-inorganic perovskite thin-films for optoelectronic applications is to be achieved. Many fabri- cation techniques have been utilized previously to develop high-performance perovskite layers but there remains an absence of a unifying model that describes accurately the formation of these materials from solution. The present study provides a thorough analysis of nucleation and growth kinetics underpinning the development of hybrid organic-in- organic perovskite thin-films. Through precise control of the perovskite growth conditions the spacing of heteroge- neous nucleation sites was varied successfully from several hundred nanometers to several hundred microns. The crystalline regions surrounding these nuclei were found to comprise clusters of highly-oriented crystal domains exceed- ing 100 pm in diameter. However, no beneficial correlation was found between the size of these well-oriented grain-clus- ters and the optoelectronic performance. The formation of the perovskite microstructure features characteristics of both classical and non-classical growth mechanisms. The insights into perovskite thin-film growth developed by the present study provide clear implications for the development of future hybrid perovskite microstructures.展开更多
The high surface energy of nanomaterials endows them a metastable nature,which greatly limits their application.However,in some cases,the degradation process derived from the poor stability of nanomaterials offers an ...The high surface energy of nanomaterials endows them a metastable nature,which greatly limits their application.However,in some cases,the degradation process derived from the poor stability of nanomaterials offers an unconventional approach to design and obtain functional nanomaterials.Herein,based on the poor stability of ZnSe-[DETA]0.5 hybrid nanobelts,we developed a new strategy to chemically graphitize and functionalize graphene oxide(GO).When ZnSe[DETA]0.5 hybrid nanobelts encountered a strong acid,they were attacked by H^+cations and could release highly reactive Se^2−anions into the reaction solution.Like other common reductants(such as N2H4·H2O),these Se^2−anions exhibited an excellent ability to restore the structure of GO.The structural restoration of GO was greatly affected by the reaction time,the volume of HCl,and the mass ratio between GO and ZnSe[DETA]0.5 nanobelts.By carefully controlling the reaction process and the post-processing process,we finally obtained several Se-based reduced GO(RGO)nanocomposites(such as ZnSe/Se-RGO,ZnSe-RGO,and Se-RGO)and various selenide/metal-RGO nanocomposites(such as Ag2Se-RGO,Cu2Se-RGO,and Pt-RGO).Although the original structure and composition of ZnSe[DETA]0.5 nanobelts are destroyed,the procedure presents an unconventional way to chemically graphitize and functionalize GO and thus provides a new material synthesis platform for nanocomposites.展开更多
基金the financial support from the Australian Renewable Energy Agency (ARENA)the Australian Centre for Advanced Photovoltaics (ACAP)the ARC Centre of Excellence in Exciton Science
文摘A heightened understanding of nucleation and growth mechanisms is paramount if effective solution processing of organic-inorganic perovskite thin-films for optoelectronic applications is to be achieved. Many fabri- cation techniques have been utilized previously to develop high-performance perovskite layers but there remains an absence of a unifying model that describes accurately the formation of these materials from solution. The present study provides a thorough analysis of nucleation and growth kinetics underpinning the development of hybrid organic-in- organic perovskite thin-films. Through precise control of the perovskite growth conditions the spacing of heteroge- neous nucleation sites was varied successfully from several hundred nanometers to several hundred microns. The crystalline regions surrounding these nuclei were found to comprise clusters of highly-oriented crystal domains exceed- ing 100 pm in diameter. However, no beneficial correlation was found between the size of these well-oriented grain-clus- ters and the optoelectronic performance. The formation of the perovskite microstructure features characteristics of both classical and non-classical growth mechanisms. The insights into perovskite thin-film growth developed by the present study provide clear implications for the development of future hybrid perovskite microstructures.
基金This work was supported by the National Natural Science Foundation of China(21431006,51732011,21761132008 and 21805189)the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(21521001)+3 种基金the Key Research Program of Frontier Sciences,Chinese Academy of Sciences(CAS)(QYZDJ-SSW-SLH036)the National Basic Research Program of China(2014CB931800)and the Excellence and Scientific Research Grant from Hefei Science Center of CAS(2015HSC-UE007).This work was partially carried out at the Center for Micro and Nanoscale Research and Fabrication,USTC.Xu L is grateful for the funding support from China Postdoctoral Science Foundation(2018M630711 and 2019T120540)and the Natural Science Foundation of Guangdong(2018A030310617).
文摘The high surface energy of nanomaterials endows them a metastable nature,which greatly limits their application.However,in some cases,the degradation process derived from the poor stability of nanomaterials offers an unconventional approach to design and obtain functional nanomaterials.Herein,based on the poor stability of ZnSe-[DETA]0.5 hybrid nanobelts,we developed a new strategy to chemically graphitize and functionalize graphene oxide(GO).When ZnSe[DETA]0.5 hybrid nanobelts encountered a strong acid,they were attacked by H^+cations and could release highly reactive Se^2−anions into the reaction solution.Like other common reductants(such as N2H4·H2O),these Se^2−anions exhibited an excellent ability to restore the structure of GO.The structural restoration of GO was greatly affected by the reaction time,the volume of HCl,and the mass ratio between GO and ZnSe[DETA]0.5 nanobelts.By carefully controlling the reaction process and the post-processing process,we finally obtained several Se-based reduced GO(RGO)nanocomposites(such as ZnSe/Se-RGO,ZnSe-RGO,and Se-RGO)and various selenide/metal-RGO nanocomposites(such as Ag2Se-RGO,Cu2Se-RGO,and Pt-RGO).Although the original structure and composition of ZnSe[DETA]0.5 nanobelts are destroyed,the procedure presents an unconventional way to chemically graphitize and functionalize GO and thus provides a new material synthesis platform for nanocomposites.
