Buried Interface Passivation with "Super-Choline" Glycerophosphocholine for Efficient Regular Perovskite Solar Cells

The device performance of efficient regular n-i-p perovskite solar cells (PSCs) is closely related to the SnO₂/perovskite buried interface, yet the buried interface often suffers from defects that cause interfacial recombination and hinder charge extraction. Here, we first introduced l-α-glycerophosphocholine (GPC), a "Super-Choline" molecule, as a bifunctional modifier at the SnO₂/perovskite interface. The glycerol group of GPC passivates oxygen vacancies on SnO₂, while the phosphocholine moiety coordinates with Pb²⁺ and I^- defects, forming a molecular bridge that suppresses recombination and enhances charge transport. Moreover, we also used 4-tert-butylpyridine as an additive in perovskite precursor to reduce PbI₂ secondary phase and improve crystallinity. As a result, the optimized PSCs exhibited a champion power conversion efficiency (PCE) of 25.31% and an impressive open-circuit voltage of 1.213 V, which is one of the smallest "V_oc loss" values (0.347 V) for the hybrid PSCs using a two-step method. Furthermore, the unencapsulated devices maintain 83% of their original PCE after being aged in N₂ for 1300 h. This work highlights GPC's "Super-Choline" functionality as an effective approach for buried interface engineering toward high-performance PSCs.