Optical absorption tuning and structural insights in Cs2AgInCl6 double perovskites through Cu and Fe cations substitution

The excellent optical and electrical properties of the organic-inorganic Pb-based halide perovskite make them promising candidates in the field of optoelectronics. However, issues with stability and toxicity prevent these materials from being commercialized. Recently, halide double perovskites have attracted remarkable attention due to their promising optoelectronic properties, stability and non-toxicity. In this study, double perovskite Cs2AgInCl6 particles were successfully synthesized by precipitation method in HCl. Moreover, the effect of Cu (replacing Ag) and Fe (replacing In) cations doping on the structural, morphological, optical, and electrical properties was investigated. The pure sample exhibited two band gaps, 4.1 eV for the allowed transition and 3.1 eV for the parity-forbidden transition. On the other hand, the doped samples exhibit only one transition, with the band gap of the Cu-doped sample at 2.10 eV, while the Fe-doped sample is at 2.36 eV. Additionally, the Cu-doped sample exhibited lower dark current and improved photoresponse compared to the other samples. Although the Cu incorporation was lower than expected based on the experimental composition, it positively affected the optoelectronic properties of Cs2AgInCl6, making it a promising material for solar cells and photodetectors.