Interface‐Triggered Bulk Electrical Coupling in SnO ₂ via Mesoscopic Chemical Reconfiguration for Scalable, High‐Efficiency Perovskite Photovoltaics

Abstract

ABSTRACT The efficiency and stability of n‐i‐p PSCs are often hindered by energy losses and defect‐induced interfacial failure, fundamentally stemming from mesoscopic surface chemical mismatch in SnO 2 nanocrystals. Herein, we propose a surface reconstruction strategy utilizing in situ generated [Al(OH) 4 ] − ions to rebuild the surface electrical double layer. This approach not only yields monodisperse, highly stable SnO 2 colloids but also synergistically passivates deep‐level defects arising from hydroxyl groups and oxygen vacancy clusters. The resulting amorphous Sn‐AlO x layer induces a surface electrostatic potential, significantly enhancing electrical coupling within the ETL bulk and establishing a robust carrier transport pathway. Consequently, we achieved champion efficiencies of 26.70% (certified 26.64%) for small‐area cells and 24.56% (certified 24.22%) for mini‐modules (21.50 cm 2 ). Notably, fully blade‐coated large‐area modules (65 cm 2 ) reached a high efficiency of 21.91%. By eliminating reactive sites at the buried interface, the unencapsulated devices retained 93% of their initial efficiency after 1100 h of MPPT (ISOS‐L‐2) and demonstrated a T 90 lifetime exceeding 700 h at 85°C (ISOS‐D‐2). This study provides novel insights for the large‐scale production application of SnO 2 sol‐gel in n‐i‐p perovskite solar modules.