Organic Dye/Cs₂AgBiBr₆ Double Perovskite Heterojunction Solar Cells

The photovoltaic performance of Cs₂AgBiBr₆ perovskite is limited by its light-harvesting ability owing to its broad bandgap. Here, we introduced three indoline dyes, D102, D131, and D149, to sensitize the TiO₂ electron transport layer that was employed in the Cs₂AgBiBr₆ perovskite solar cells (PSCs). The perovskite-indoline dye hybrid cells worked with higher power conversion efficiencies (PCEs) than the corresponding dye-sensitized solar cells and the PSC. Extended absorption resulted in a higher short-circuit current density, up to 8.24 mA cm^-2, and a maximum PCE of 4.23% in the case of D149, for instance. The double perovskite worked as a p-type interlayer between the dyes and spiro-OMeTAD to convey the holes from the former to the latter, resulting in enhancement in the overall performance.