Facile Synthesis of Bismuth-Based Perovskite and Solvent Engineering for Improving the Crystallinity of Lead-Free Perovskite Material: A Microstructural Exploration

In this work, bismuth based perovskite thin film has been synthesized and the different solvent precursor in lead-free methyl ammonium bismuth bromide (MABiBr3) perovskite thin film was investigated. Initially, we have focused on the bismuth based material for the synthesis of lead-free perovskite thin film, because this material is non-toxic elements and fulfil requirements of being environmentally friendly. Moreover, bismuth is relatively stable as compared to other metal halides and has a variety of uses in the commercial application field. There were three precursor solvents used i.e., N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO) and gamma-butyrolactone (GBL) for improving the crystallinity of the synthesized perovskite thin film and also increasing the efficiency of the synthesized material. Thus, the present work compared the effect of five different combinations of MABiBr3 with various solvents, i.e. only MABiBr3, MABiBr3/DMSO, MABiBr3/DMF, MABiBr3/GBL and MABiBr3 with all three DMSO, DMF and GBL. The synthesized MABiBr3 perovskite thin film was characterized by X-Ray diffraction (XRD) analysis for structural investigation and the lattice strain was estimated by the Williamson−hall plot. The results showed ordinary grain size, average interlayer spacing, dislocation density, and micro strain of MABiBr3 perovskite film. MABiBr3/DMF/DMSO/GBL showed a good average particle size. The stress of the synthesized perovskite thin film with different solvent precursor was compressive to tensile stress as the solvent variation. The combined use of all three solvent precursors show a good response to induce crystallinity of perovskite thin film.