Infrared responded and UV photostable carbon-based perovskite solar cell: Er and Sm Co-doped TiO2 nanorod arrays and enhanced photovoltaic performance

To address the two critical issues of low near-infrared (NIR) photon utilization and poor ultraviolet (UV) stability in perovskite solar cells (PSCs), this study synthesized Sm 3+ and Er 3+ co-doped TiO 2 nanorod (NRs) arrays via a hydrothermal method and employed them as the electron transport layer (ETL) for carbon-based PSCs. The incorporation of Sm 3+ and Er 3+ simultaneously improves perovskite infiltration, carrier-transport efficiency, and light absorption performance. Compared with pristine TiO 2 , the Sm/Er co-doped NRs effectively suppress non-radiative recombination, reduce series resistance, improve electron mobility, and prolong carrier lifetime. Furthermore, the introduction of Sm 3+ , Er 3+ into TiO 2 NRs weakens the radial growth of nanorods. A positive bandgap shift and a negative flat-band potential shift were observed after doping. The co-doped PSCs achieved 12 % increase in conversion efficiency when compared with the undoped device. The doped perovskite exhibited strong resistance to ultraviolet-induced degradation. The device has an infrared light efficiency of 0.15 % at the wavelength of 800–1100 nm.