TUNABLE VACANCY ORDERING FOR DEFECT TOLERANT HYBRID HALIDE SEMICONDUCTORS

Abstract

Hybrid halide perovskites have proven to be promising semiconductor materials for ap-plications in photovoltaics, neuromorphic computing, energy storage, and light-emitting diodes. Compared with conventional, well-studied semiconductors (e.g. Si, GaAs, CdTe), hybrid halide perovskites are uniquely defect-tolerant and maintain their optoelectronic properties despite having intrinsic high equilibrium defect concentrations. Tin-based hy- brid halide perovskites are a less toxic and underexplored alternative to Pb-based counter- parts, but suffer from intrinsic oxidation, uncontrolled doping, and structural disorder that limits their optoelectronic properties and applications. Here, we explore the crystal struc- tures and resulting properties of Sn-based hybrid halide perovskites materials that exhibit vacancy-ordered defects while maintaining ideal 3D structural connectivity. By synthesiz- ing multiple seven carbon diammonium organic A-site cations with Sn (II), Sb (III), and Bi (III) and characterizing the distinct optoelectronic properties of each, we aim to establish the underlying enthalpic and entropic mechanisms that permit defect tolerance and dopa- bility in hybrid halide perovskites for use in next-generation semiconducting materials.