Colloidal CsX (X = Cl, Br, I) Nanocrystals and Their Transformation to CsPbX3 Nanocrystals by Cation Exchange

摘要: We have developed a facile colloidal synthesis approach for nearly monodisperse CsX (X = Cl, Br, I) nanocrystals with truncated octahedral shape and simple cubic structure. Upon the partial exchange of Cs+ Pb2+ ions, these particles can be transformed to fluorescent CsPbX3 Br) nanocrystals. The CsBr case has been studied extensively: transformation CsPbBr3 goes through core/shell CsBr/CsPbBr3 as intermediate structures. In early stages transformation, i.e. NCs thin shells, exhibit strong blue-shifted emission compared bulk band gap due presence quantum confined domains on surface particles. These perovskite are unstable, red-shifts time. Also, undergo significant inter-particle aggregation over time if cation process is not completed. full scheme, however, yields stable mon-o...