<p>Long-term stability of perovskite modules under outdoor conditions remains challenging, hindering their commercialization. Defect evolution driven by charge accumulation is as a key factor deteriorating the performance of perovskite optoelectronic devices. Here we introduce an amorphous (shell)–crystalline (core) silicon nitride (Si₃N₄) nanocomposite at the buried interface of perovskite solar cells. The composite acts as a nano-cacher that mitigates charge accumulation and suppresses defect evolution. The amorphous shell, with a low density of unsaturated dangling bonds, effectively passivates surface defects of the perovskite film. Simultaneously, the trapping centres within the crystalline Si₃N₄ core capture accumulated charge carriers during device operation, progressively enhancing the internal electric field. This, in turn, improves charge extraction efficiency and suppresses defect evolution driven by charge accumulation. The resulting perovskite solar cells and minimodules with an area of 10.86 cm² achieve a power conversion efficiency of 26.65% (certified 26.37%) and 23.17% (certified 22.2%), respectively. Moreover, large perovskite modules (area 1,252 cm²) maintain stable power output over 6 months of outdoor operation.</p>