Physical Property Dependence on Dimensionality in Hybrid Halide Perovskites

Abstract

Light-harvesting 3D organic-inorganic hybrid halide perovskites ABX3 have been attracting considerable attention due to their excellent photovoltaic performance and optoelectronic properties. Tuning in their electronic and crystal structures and photoelectric conductivity is at the heart of idealization of new materials, novel functionalities and/or improving the efficiency of optoelectronic devices. Their important physical properties include suitable and adjustable band gaps, low exciton binding energy, very large optical absorption coefficients across the visible solar spectrum, long hole-electron diffusion length leading to efficient charge separation/collection, and high defect tolerance. However, despite the great progress in efficiency, the major drawbacks of the hybrid halide perovskites are the instability under ambient conditions. Compared with the conventional 3D perovskite ABX3, the low-dimensional family exhibits better environmental stability and more varied compositions, electronic and crystal structures. In this project, we intend to obtain a better understanding on the synthesis, chemical, and physical properties of low dimensional 0D and 2D organic-inorganic halide perovskites with general formula (OM)2An¿1BnX3n+1 (n = 1, 2, 3, 4...), where OM is organic molecules, A is monovalent cation, B is a divalent metal cation, X is a halide anion, and n represents the number of [BX6]4¿ octahedral layers. The variation of dimensionality, organic cation, and the number of layers in the 2D structure can lead to the change of crystal structure, chemical and physical properties which offer a broad opportunity for materials and physical phenomenon discoveries and new technological applications. Study the dimensionality dependence on physical properties can give more knowledge and insight for designing new perovskite devices.