Polymer-Doped SnO₂ as an Electron Transport Layer for Highly Efficient and Stable Perovskite Solar Cells

To produce highly efficient and repeatable perovskite solar cells (PSCs), comprehending interfacial loss and developing approaches to ameliorate interfacial features is essential. Nonradiative recombination at the SnO₂-perovskite interface in SnO₂-based perovskite solar cells (PSCs) leads to significant potential loss and variability in device performance. To improve the quality of the SnO₂ electron transport layer, a novel polymer-doped SnO₂ matrix, specifically using polyacrylic acid, was developed. This matrix is formed by spin-coating a SnO₂ colloidal solution that includes polymers. The polymer aids in dispersing nanoparticles within the substrate and is evenly distributed in the SnO₂ solution. As a result of the polymer addition, the density and wetting properties of the SnO₂ layer substantially improved. Subsequently, perovskite-based photovoltaic devices comprising SnO₂ and Spiro-OMeTAD layers and using (FAPbI₃)_0.97(MAPbBr₃)_0.03 perovskite are constructed. These optimized devices exhibited an increased efficiency of 17.2% when compared to the 15.7% power conversion efficiency of the control device. The incorporation of polymers in the electron transport layer potentially enables even better performance in planar perovskite solar cells.