Calotropis-mediated biosynthesis of TiO2@SnO2/Ag nanocomposites for efficient perovskite photovoltaics.

In this study, green SnO 2 @TiO 2 nanocomposites were initially synthesized using an extract from the Calotropis plant as an electron transfer material for fabricating perovskite solar cells (PSCs). Further, plasmon impregnation (Ag-NPs) into the SnO 2 @TiO 2 nanocomposites yielded nanocomposite (TiO 2 @SnO 2 /Ag) films. The effect of doping silver into the SnO 2 @TiO 2 nanocomposites was investigated in detail to gain insights into how it influences the photovoltaic performance of the PSC. It resulted in enhanced quenching of photoluminescence compared to TiO 2 and TiO 2 @SnO 2 electron transport layers (ETLs), indicating faster charge extraction. PSCs utilizing the TiO 2 @SnO 2 /Ag ETL showed significantly improved performance with a power conversion efficiency of 22.2 %, a higher fill factor, and reduced hysteresis compared to cells with TiO 2 and TiO 2 @SnO 2 ETLs. The characterization of the nanocomposites revealed that the TiO 2 @SnO 2 /Ag ETL led to perovskite films with improved crystallinity, morphology, charge separation, and transfer properties. Electrochemical impedance spectroscopy confirmed the TiO 2 @SnO 2 /Ag ETL facilitated faster charge transfer and lower recombination at interfaces. Finally, the TiO 2 @SnO 2 /Ag ETL-based devices exhibited superior long-term stability in air, maintaining over 87 % of their initial efficiency. This work demonstrates that the incorporation of TiO 2 @SnO 2 /Ag nanocomposites is effective for developing high-performance and stable PSCs. • Green SnO 2 @TiO 2 nanocomposites were initially synthesized using an extract from the Calotropis plant. • Ag NPs were doped into the SnO 2 @TiO 2 nanocomposites. • PSCs were fabricated with TiO2@SnO2/Ag as electron transport layer. • The optimized cell showed an efficiency of 22.2 %. [ABSTRACT FROM AUTHOR]