2-Methoxy Ethanol-Driven Solvent Engineering of Cs3Bi2I9 Perovskite Films and its Impact on Lead Free Perovskite Solar Cell Devices

Abstract

The development of compact perovskite thin films is essential for fabrication of high-performance solar cell devices. Solvent engineering stands out as a promising method to achieve such films, providing a straightforward approach with significant control over the film formation process. In this study, we employed a solvent engineering approach to attain compact and uniform growth in Cs₃Bi₂I₉ films. We incorporated 2-methoxy ethanol (2-ME) as an additive in N, N-Dimethylformamide (DMF) solvent. The resulting perovskite films exhibited enhanced crystallinity and absorbance compared to films prepared with DMF alone, particularly when using a DMF:2-ME mixing ratio of 4:1. Moreover, we successfully fabricated lead-free, flexible perovskite solar cell devices using a solution processing technique. The photovoltaic performance of estimated and efficiency of devices prepared with 4:1 ratio of DMF:2-ME exhibited efficiency of ~1.56%.