Enhanced Electron Collection and Light Harvesting of CH₃NH₃PbI₃ Perovskite Solar Cells Using Nanopatterned Substrates

In this study, a CH₃NH₃PbI₃-based perovskite solar cell (PSC) with high power conversion efficiency (PCE) has achieved by incorporating a nanopatterned fluorine-doped tin oxide (FTO) substrate (NPFS). This NPFS-PSC is prepared with different structural depths (100, 150, and 200 nm) using both self-assembly and sphere lithography techniques. As determine through the optical and electrical analysis of different PSC devices, the NPFS-PSCs not only display the enhanced light absorption (due to the 2D diffraction grating) but also improve the electron collection efficiency by increasing the FTO/electron transport layer (ETL) and ETL/perovskite effective interface area. Compared to a planar PSC, the photocurrent density of the 200 nm etched NPFS-PSC is enhanced from 19.27 to 23.81 mA cm⁻² leading to an increase in the PCE from 14.21% to 17.85%. These results indicate that introducing the NPFS into the TiO₂-based PSC can improve both light absorption ability and electron extraction and, therefore, represents a novel, promising, high-performance photovoltaic device.