Double\nPerovskite\nInterlayer Stabilized Highly Efficient\nPerovskite Solar Cells

Metal halide perovskite solar cell\n(PSC) technology has\nan impressive\npower conversion efficiency (PCE) exceeding 26.1% and demonstrates\ncost-effective manufacturing. However, the stability of these PSCs\nposes a significant challenge, hindering their widespread manufacturing\nand commercialization. To tackle the degradation issue inherent in\nPSCs, surface passivation techniques, particularly employing a thin\nlayer of two-dimensional (2D) perovskites, create a 2D/3D heterostructure.\nBeyond this, the exploration of metal halide double perovskites adds\na new dimension to the chemical and band gap phase space of materials\nfor optoelectronic applications. In this study, we leverage a wide\nband gap double perovskite interlayer to enhance the stability of\n3D metal halide perovskite. Specifically, the double perovskite nanoparticle\nCs<sub>2</sub>AgBiBr<sub>6</sub>, with its substantial band gap of\n2.2 eV and exceptional air stability, is utilized. Through optimization,\na Cs<sub>2</sub>AgBiBr<sub>6</sub>-treated PSC achieves an open-circuit\nvoltage of 1.12 V and an impressive PCE of 19.52%. Additionally, the\nCs<sub>2</sub>AgBiBr<sub>6</sub> passivation layer proves to be effective\nin bolstering the stability of PSCs. This work demonstrates an additional\nstrategy and design motif to simultaneously increase the PCE of PSCs\nalong with achieving improved stability.