Efficient printable carbon-based mesoscopic perovskite solar cells based on aluminum and indium doped TiO₂ compact layer

Titanium dioxide (TiO₂) is commonly used in high-performance carbon-based mesoscopic perovskite solar cells (C-MPSCs), but its relatively low charge mobility and severe carrier accumulation hinder further improvements in device performance. Here, we demonstrate the use of aluminum and indium co-doped TiO₂ (AlIn-TiO₂) as compact layers for highly efficient C-MPSCs. AlIn co-doping not only optimizes the band alignment at the AlIn-TiO₂/perovskite interface, but also facilitates the charge transfer of pristine TiO₂. As a result, the performance of AlIn-TiO₂-based C-MPSCs is overall improved with an efficiency of 15.53%, which is more than 15% higher than that of pristine TiO₂-based device (13.49%). This work enriches the metal doping mechanism of TiO₂ and provides a simple and feasible method for obtaining efficient printable C-MPSCs.