ABSTRACT For the PSC PV to be a competing technology with silicon and thin film PV technologies more data from field installations need to be studied and examined. In this study, we publish the results of 1 year monitoring of two single‐junction perovskite modules (each with a module area of 0.7164 m 2 ) outdoors. The modules were monitored throughout the year from June 2024 to June 2025, mounted on fixed racks, 45° tilted and south‐facing at the European Solar Test Installation (ESTI) in northern Italy (humid subtropical climate). Before the modules were exposed to natural sunlight, a measurement protocol was developed under simulated sunlight indoors to ensure stable measurements; this resulted in an optimal I–V sweep time of 10 s, which was then applied under simulated sunlight as well as under natural sunlight. The module YZ517 showed relatively stable results with a decrease in efficiency eta of about 3 percentage points from June 2024 to June 2025, while the YZ518 module showed greater decrease and was therefore not used for further investigation in the study. Temperature coefficients were determined for 1000 Wm −2 as δ P max − 0.054 %C −1 , β V OC −0.09 %C −1 and α I SC 0.089 %C −1 .
Ellis et al. (Thu,) studied this question.