Exploring a Lead‐free Semiconducting Hybrid Ferroelectric with a Zero‐Dimensional Perovskite‐like Structure

Abstract

Perovskite lead halides (CH 3 NH 3 PbI 3 ) have recently taken a promising position in photovoltaics and optoelectronics because of remarkable semiconducting properties and possible ferroelectricity. However, the potential toxicity of lead arouses great environmental concern for widespread application. A new chemically tailored lead‐free semiconducting hybrid ferroelectric is reported, N ‐methylpyrrolidinium) 3 Sb 2 Br 9 ( 1 ), which consists of a zero‐dimensional (0‐D) perovskite‐like anionic framework connected by corner‐ sharing SbBr 6 coordinated octahedra. It presents a large ferroelectric spontaneous polarization of approximately 7.6 μC cm −2 , as well as notable semiconducting properties, including positive temperature‐dependent conductivity and ultraviolet‐sensitive photoconductivity. Theoretical analysis of electronic structure and energy gap discloses a dominant contribution of the 0‐D perovskite‐like structure to the semiconducting properties of the material. This finding throws light on the rational design of new perovskite‐like hybrids, especially lead‐free semiconducting ferroelectrics.