Degradation of perovskite solar cells: Insights from accelerated testing versus outdoor aging in two climate zones

• Encapsulation of four-pixel PSC device with PIB edge seal demonstrated strong resistance to external environmental factors. • Outdoor tests showed strong correlation between device degradation and combined effect of climatic and operating conditions. • Testing under different load showed that OC condition accelerates degradation more than MPP or SC. • Suns-JV analysis demonstrated sequential degradation modes during aging, with shunting followed by bulk defect formation. In this study, we present our latest developments in encapsulating perovskite solar cells (PSC) with polyisobutylene (PIB). We evaluate the performance of devices under accelerated aging protocols including light soaking and damp heat (DH) and compare these results to outdoor (ISOS-O-2) performance in two distinct climates: the hot-summer Mediterranean climate, Csa (Madrid, Spain), and the hot-summer humid continental climate, Dfb (Gdańsk, Poland). Additionally, we explore the prevailing failure modes within the devices during these stability tests based on light intensity-dependent current density–voltage (suns-JV) analysis. Light soaking testing revealed photoinstability, with T 80 occurring after 740 h. Outdoor testing in Madrid resulted in device degradation, as evidenced by a significant drop in power output, whereas stable operation was maintained in Gdańsk. This difference in device behavior may be influenced by various factors, including climate conditions, operating mode, mounting configuration, and measurement frequency, as the tests were conducted under different setups. Further analysis of the operating conditions in the outdoor test conducted in Gdańsk showed that open-circuit (OC) accelerates degradation strongly, while maximum power point (MPP) and short-circuit (SC) imposed progressively less stress. These findings lay the groundwork for future efforts to correlate specific performance parameters across different research groups. This will ultimately pave the way for a comprehensive test protocol applicable across all climatic zones and directly linkable to accelerated aging studies.