Locating the Non-Radiative Recombination Losses of Perovskite Solar Cells During Accelerated Ageing

The commercialization of perovskite solar cells (PSCs) depends on breakthroughs in stability, yet the complex degradation mechanisms complicate the study of their long-term performance. This work investigates the role of defects in PSC stability by establishing a quantitative link between defect-related parameters and device performance. We found that minimal losses in open-circuit voltage (V_OC) were accompanied by significant reductions in charge extraction efficiency (J_SC and fill factor). Through non-destructive, contactless optical characterization, we decoupled non-radiative recombination effects in various perovskite stacks before and after accelerated ageing. Our results show that non-radiative recombination in the perovskite bulk enhances greatly during the first 50 hours of photothermal aging, dominating overall recombination losses. Consequently, optimizing material composition and improving crystal quality to suppress defect formation can extend photothermal stability by over 50-fold.