Structural Phase Transition and Optical Properties in New 0D Hybrid Halide Perovskite: (DMP)2MCl5 (M = Bi, Sb)

Abstract

Exploration of novel materials with high energy conversion efficiency that can harvest energy from inexhaustible sources is highly required to solve the present need for energy. In this context, metal halide perovskites have emerged as low-cost, highly efficient novel photovoltaic and luminescent materials due to their high carrier mobility, remarkably long carrier diffusion lengths, and tunable optical band gaps. The conventional lead-based metal halide perovskites offer excellent photovoltaic and luminescent properties. However, lead-based halide perovskites' environmental toxicity and poor stability have become key bottlenecks towards their future application and commercialization. [1] Thus, the search for materials with outstanding optoelectronic and photovoltaic properties, containing non-toxic elements with excellent stability to air and moisture, is highly crucial. In recent years, Bi/Sb-based lead-free hybrid organicinorganic metal halide perovskites with zero-dimensional structures have attracted unparalleled attraction owing to their eco-friendly nature, fascinating luminescent and photovoltaic properties, and excellent stability due to their unique crystallographic structures with isolated inorganic metal halide clusters protected by organic shells and superior optical properties. These intriguing properties of 0D hybrid metal halide perovskites make them promising candidates for commercial applications in solar cells, LED applications, and X-ray detectors. [2] To further explore the 0D lead-free hybrid metal halide perovskites, herein we report two novel organic ammonium-based 0D lead-free metal halide perovskites, (DMP)2BiCl5 and (DMP)2SbCl5 that crystallize in the triclinic system with P1ത space group and monoclinic system with P21/c space group, respectively. The crystal structure consists of discrete isolated [M2Cl10] 4− (M = Bi, Sb) inorganic units encased by (DMP)+ organic cations as confirmed by single crystal study. The phase purity, structural phase transition, stability, and optic