Solvents driven structural, morphological, optical and dielectric properties of lead free perovskite CH3NH3SnCl3 for optoelectronic applications: Experimental and DFT study

Abstract

Solvent engineering is a powerful technique to achieve high performance Organic-Inorganic Halide Perovskites (OIHPs) which emerged as a potential candidate for various optoelectronic applications. In the present work, lead free CH3NH3SnCl3 perovskites were prepared using two different mixed solvents namely N, N-dimethylformamide (DMF): Dimethylsulfoxide (DMSO) and N, N-dimethylformamide (DMF): Acetonitrile (ACN). The effect of these two solvents mixture on the structural, morphological and optical properties of CH3NH3SnCl3 was analysed. The obtained two perovskites samples were investigated by XRD, TGA, FESEM, EDAX, FT-IR, UV-vis spectroscopy (UV-vis), Photoluminescence spectroscopy (PL) and dielectric spectroscopy. To gain insight into the optical behaviour, the first principle calculations were also performed. FESEM images revealed a conspicuous variation for the two solvents. The DMF:ACN based perovskite possesses band gap more than that for DMF:DMSO based perovskite. The DFT calculations also show the same trend for the energy gap. PL emission is found to enhance in the case of DMF:DMSO based perovskite. The dielectric constant and dielectric loss values have demonstrated the influence of solvents. The analysis shows that among the two cases, the DMF: DMSO solvent mix is found to show results better than that of DMF: ACN case.