Spatial Molecular Engineering of Hole Semiconductors Enables Record Efficiency and Durability in Inverted Perovskite Solar Cells

Abstract

ABSTRACT Conventional small‐molecule hole‐transporting materials (SM‐HTMs), although morphologically robust, typically suffer from limited hole mobility, interfacial energy misalignment, and inefficient charge extraction, which collectively hinder power conversion efficiencies (PCEs) above 25% in inverted perovskite solar cells (PSCs). Herein, breaking from conventional design paradigm, novel spatial molecular engineering was targeted proposed for SM‐HTMs to overcome inherent limitations while reinforcing advantages. By spatially exposing the functional heterocyclic core to release its full potential, the tailored WH13 dramatically enhances the perovskite/HTM interfacial interactions, promotes crystallization, and facilitates hole extraction. More importantly, the resultant planar‐steric architecture enables long‐range π‐stacking order while supporting nanocrystal‐level film‐formation, thereby achieving an optimal balance between charge transport dynamics and morphological features. Consequently, WH13‐based inverted PSCs achieve a champion PCE of 26.6% (certified 26.24%) with exceptional operational stability (>99%, ISOS‐L‐1 500 h), representing the highest efficiency reported to date for SM‐HTM‐based PSCs. This spatial molecular engineering strategy establishes a generalizable design paradigm for next‐generation HTMs, opening a promising pathway toward high‐performance, operationally stable, and commercially viable PSCs.