Experimental investigation of structural and photophysical nature of non-toxic Cs2AlBiCl6 double perovskite for photovoltaic applications

In recent years, inorganic halide based non-toxic double perovskite (DP) has emerged as a promising group of materials that are more stable than hybrid lead-based organic and inorganic perovskite materials for green energy applications. In this work, first time we report the synthesis of a new inorganic non-toxic halide-based double perovskite Cs2AlBiCl6 by a simple room-temperature synthesis technique. The structural properties of the synthesized material has been observed by using X-Ray diffraction (XRD). The observed peaks of XRD were found to be in good agreement with the reference data. To envisage the photo physical properties, we have done the photoluminescence (PL) spectroscopy of the synthesized material at low temperature (19 K) and high temperature (300 K). It is clear from the PL spectra that the main peak has been observed around 424 nm corresponding to 2.9 eV energy which also confirms the luminescent behavior of the material. The observed peak in the PL spectra is due to phonon-assisted carrier recombination of the excitons. Also, the PL intensity at low temperature (19K) is high as compared to high temperature (300K) due to a decrease in carrier recombination rate with an increase in temperature. This novel work opens a new path for the synthesis of non-toxic double perovskite materials for photovoltaic and green energy applications.