Internal Photon Management via Constructing Nanoconvex SnO ₂ for High‐Performance Perovskite Solar Cells and Modules

ABSTRACT Despite rapid advances in the power conversion efficiency (PCE) of perovskite solar cells (PSCs) over the past decade, notorious optical and non‐radiative recombination losses still hinder the performance from reaching the Shockley–Queisser (S–Q) limit. Here, we introduce a multifunctional tin oxide (SnO 2 ) electron transport layer with periodic nanoconvex (NC) morphology, constructed through histidine hydrochloride hydrate (His‐HCl·H 2 O)‐induced colloidal self‐assembly. The nanostructure enhances broadband light harvesting through Mie scattering and resonant coupling, as confirmed by finite‐difference time‐domain (FDTD) simulations. Concurrently, amino and carboxyl groups from his interact with uncoordinated ions at the SnO 2 /perovskite interface, suppressing trap density and optimizing energy band alignment. Ultimately, the best‐performing device achieves a PCE of 26.51% (certified 26.11%) and retains 87% of its initial efficiency after continuous maximum power point tracking for 1200 h. Scaled‐up devices also exhibit impressive performance, with champion PCEs of 25.96% and 23.67% for 1.0 cm 2 cell and 17.1 cm 2 mini‐module, respectively.