Multifunctional Acetaminophen Interlayer for High Efficiency and Durability Lead-Lean Perovskite Solar Cells

Due to the easy oxidation of Sn²⁺, which leads to form tin vacancy defects and poor perovskite film quality, caused by the rapid crystallization rate in tin-based perovskite solar cells (PSCs), their efficiency lags far behind that of lead-based PSCs. To improve the photovoltaic (PV) performance and stability of FA_0.9PEA_0.1SnI₃-based PSCs (T-PSCs), a small amount of Pb(SCN)₂ is introduced into a perovskite precursor as an antioxidant, and acetaminophen (ACE) with various functional groups is used to modify a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/perovskite interface. The results show that the Pb(SCN)₂ additive and ACE interfacial modification can not only optimize energy level alignment in T-PSCs but also inhibit Sn²⁺ oxidation to reduce the trap-state density, resulting in promoted carrier transport. The synergetic effect of the Pb(SCN)₂ antioxidant and ACE interfacial modification significantly reduces nonradiative recombination and improves the PV performance and stability of T-PSCs. Consequently, the unsealed T-PSCs with the Pb(SCN)₂ additive and ACE modification achieve a champion efficiency of 12.04% and maintain 99% of their initial PCE after being stored in N₂ for more than 2100 h, while reference T-PSCs demonstrate a champion PCE of 6.20% and retain only 72% of its initial PCE. Moreover, the modified T-PSCs without encapsulation demonstrate much better stability in humid air.