Locating Non-Radiative Recombination Losses and Understanding Their Impact on the Stability of Perovskite Solar Cells During Photo-Thermal Accelerated Ageing

Commercialization of perovskite solar cells (PSCs) requires further breakthroughs in stability, but the complex degradation mechanisms and the interplay of the underlying stress factors complicate insight-driven improvement of long-term stability. This study establishes a quantitative link between potential degradation—specifically open-circuit voltage (V_OC) and quasi-Fermi level splitting (QFLS)—and the photo-thermal stability of PSCs. It is highlighted that an increase in non-radiative recombination losses induces the seemingly negligible decrease in V_OC and QFLS, though it causes a significant decrease in fill factor (FF) and/or short circuit current (J_SC) instead, leading to an overall performance decline. By combining non-destructive photoluminescence imaging and drift-diffusion simulations, it is revealed that during photo-thermal ageing, unstable low-dimensional passivation fails within tens of hours, generating bulk defects, while unstable hole-transport-layer contacts induce interface defects within hours. Building on these findings, a robust hole-transport-layer polymer interface is employed and enhanced perovskite crystal quality to suppress both interface and bulk defect generation during ageing, achieving a T₈₀ lifetime exceeding 1000 h under accelerated ageing conditions (85 °C and two-sun illumination).