Crystallization modulation investigation on a 0D/2D mixed dimensional lead-free cesium bismuth iodide perovskite

Perovskites comprising of cesium bismuth iodide exhibit remarkable environmental stability and hold significant potential for diversity applications in the optoelectronics domain. Even though uneven surface coverage with pinholes and high surface roughness are some of the primary obstacles preventing its widespread use as a photovoltaic absorber material . Herein the tailoring of surface morphology through solvent controlled growth approach and anti-solvent treatment is reported on a 0D/2D mixed dimensional cesium bismuth iodide perovskite films. Solvent controlled growth (scg) approach improved the crystallinity and morphology of the perovskite film. The ideal solvent-controlled time found to be 45 min. As a result, the charge carrier life time was doubled and power conversion efficiency was increased from 0.3 % to 0.89 %. The scg crystallization also enhanced the growth of a 2D-BiI 3 phase, leading to bandgap reduction from 1.82 to 1.76 eV. However, only slight improvement was observed in charge carrier lifetime, grain growth size and film compactness, absorption intensity or overall PCE upon utilization of chlorobenzene as anti-solvent. • Fabrication of lead-free, all-inorganic perovskite solar cell via Solvent-controlled growth mechanism. • Improvement in crystallinity and morphology is observed. • The solvent-controlled growth crystallization enhances the growth of the 2D-BiI 3 phase. • Band gap reduction from 1.82 to 1.76 eV can be observed. • A threefold increase in power conversion efficiency is recorded.