Controlling Cs₂PbX₄ Nanostructure Formation via Solution Processing for Robust Cesium-Based Perovskite Solar Cells

This study investigates the incorporation of low-dimensional (LD) inorganic materials for interfacial engineering in perovskite solar cells (PSCs) through solution processing methods. While LD perovskite nanostructures have shown promise for enhancing device performance in cesium-based PSCs, the underlying growth mechanisms remain underexplored. The work demonstrates how controlling the solvent evaporation dynamics during solution processing modulates the nanomorphology of Cs₂PbX₄. An evolution of Cs₂PbX₄ nanostructure growth is observed on CsPbI₂Br thin films. Nanostructures grown from CsPbI₂Br are shown to introduce a beneficial passivation effect, improving the interface quality with the hole transport layer (HTL). Systematic characterization reveals that carefully engineered LD nanostructure morphologies strongly impact the optoelectronic properties of PSCs. Optimized CsPbI₂Br/Cs2PbX₄ heterostructures enhance the power conversion efficiency by an average of 25.5% compared to devices without interfacial engineering. Under long-term photovoltaic aging and post-irradiation testing simulating low Earth orbit conditions, the optimized devices maintain over 87.5% of their initial efficiency, demonstrating improved stability. The findings provide new insights into controlling the morphology of inorganic LD nanomaterials through solution processing parameters. The promising stability results highlight the potential of this approach for robust PSC performance in harsh operating environments.