Enhanced Performance\nand Stability of CsPbBr<sub>3</sub> Perovskite Solar Cells Using Trioctylphosphine\nOxide Additive

This study investigates the application of trioctylphosphine\noxide\n(TOPO) and triphenylphosphine oxide (TPPO) as an additive to enhance\nthe performance of all-inorganic CsPbBr<sub>3</sub> perovskite solar\ncells (PSCs). The addition of TOPO and TPPO passivates surface defects,\nincreases grain size, and reduces surface trap states, leading to\nbetter light absorption and accelerated carrier transport. These modifications\nlead to an optimized energy level distribution, resulting in a significant\nincrease in power conversion efficiency from 5.14 to 9.21% with TOPO\nand from 5.14% to 7.28% with TPPO. Furthermore, the long alkyl chains\nin TOPO provide effective isolation from air and water, significantly\nenhancing device stability for over 2400 h without packaging. The\nfindings demonstrate that oxygen phosphine additives with long alkane\nchains are more effective in improving PSCs than those with aromatic\nhydrocarbons, offering new insights for the use of passivators in\nperovskite solar cells.