Defect-Immune Perovskite Photovoltaics via Molecular Vise Engineering: A Pathway to Scalable, Encapsulation-Free Production under Mild Conditions

The interfacial defects induced by halide ion migration critically limit the performance scalability of solution-processed perovskite solar cells (PSCs). Here, we demonstrate an engineering strategy using zwitterionic potassium hydrogen phthalate (KHP). This approach synergistically regulates crystallization dynamics and passivates multidimensional defects via atomic-scale interface anchoring. Time-resolved AFM characterization reveals that the amphiphilic KHP, with C═O/Pb 2+ coordination capability, induces self-assembled boundary confinement during perovskite crystallization, generating ultrasmooth films with 68% reduced surface roughness (average roughness ( R a ) = 62 nm vs control 112 nm). Multinuclear ( 1 H/ 207 Pb) NMR analyses decipher the dual-anchoring mechanism, where KHP coordinates Pb 2+ via carboxyl oxygen ( 207 Pb upfield shift Δδ = 1020 ppm, [PbI 6 ] 4– → [PbI 5 (OOCR)] 3– ) while forming NH 3 ···HOOC – hydrogen bonds with the hydrogen phthalate anion (HP – ) (2D COSY J -coupling at 7.95 ppm), synergistically immobilizing halides through this molecular vise effect as corroborated by XPS-derived Pb 2+ reduction (Pb 4f 7/2 peak shift of 1.25 eV). The dual passivation mechanism involving both Pb defects and halide vacancies enables a record PCE of 6.17% for air-processed low-cost PSCs, achieving absolute efficiency enhancement over the baseline. Herein, ambient-air fabricated perovskite solar cells via zwitterion-mediated interface anchoring achieve 6.17% efficiency and 71.12% stability (360 h), with enhanced moisture resistance (contact angle: 31° → 59°), enabling scalable low-cost production under noninert conditions.