FOXES results have contributed to shed light on the factors that limit the operational stability of perovskite solar cells (PSC).
An extensive work headed by the University of Potsdam has identified mobile ion-induced internal field screening is the dominant factor in the degradation of PSC under operational conditions. The increased field screening leads to a decrease in the steady-state efficiency, often owing to a large reduction in the current density. Instead, the efficiency at high scan speeds (>1,000 V s−1), where the ions are immobilized, is much less affected. We also show that the bulk and interface quality do not degrade upon ageing, yet the open-circuit voltage decreases owing to an increase in the mobile ion density. This work reveals the importance of ionic losses for intrinsic PSC degradation before chemical or extrinsic mechanical effects manifest.
The results have been reported in Nature Energy.