Dual-Functional Top-Interface Passivation Using a Thiohydantoin Derivative for High-Performance Perovskite Solar...

The efficiency and stability of inverted perovskite solar cells (PSCs) are primarily limited by substantial nonradiative recombination losses at the interfaces, particularly the perovskite (PVK)/electron transport layer (ETL) interface. Here, we introduce a versatile passivation strategy that employs a multifunctional molecule, 3-Phenyl-2-Thiohydantoin-5-Propionic Acid (PTGA), as an interlayer at PVK/ETL interface. The ─NH─ moieties in PTGA can repair anionic surface defects through hydrogen bonding, whereas its carbonyl (C = O) functionalities in ─COOH effectively passivate the undercoordinated Pb²⁺ cations. This cooperative action leads to a marked decrease in interfacial defect concentration. As a result, the approach improves the crystallinity of the active layer, optimizes energy band alignment, boosts electron extraction efficiency, and suppresses nonradiative recombination. The treated inverted solar cells deliver a champion efficiency of 25.13% with improved long-term storage stability and persistent light illumination stability, substantially outperforming their untreated counterparts. This work provides a profound mechanistic understanding of multisite molecular passivation and delivers a simple yet effective strategy to advance the commercial prospects of perovskite photovoltaics.