Proceedings of International Conference on Hybrid and Organic Photovoltaics (HOPV23)
Publication date: 30th March 2023
In recent years perovskite solar cells (PSCs) have attracted attention due to their promising electro-optical properties leading to high power conversion efficiencies of 25.7% in single-junction devices [1]. However, the stability of PSCs is still limited and, thus, the bottleneck on their way to commercialization. One of the main causes of the poor stability is the presence of mobile ions in the perovskite absorber, facilitated by their soft ionic crystal structure. Interestingly, the density of mobile ions reported in literature spans multiple orders of magnitude reaching from 1015 - 1019 cm-3 [2, 3]. One technique that has been previously applied to quantify the activation energy, diffusion coefficient, and density of mobile ions is transient ion drift (TID). In TID, the modulation of the device capacitance due to the redistribution of mobile ions after applying a voltage pulse is measured. However, so far, the interpretation of TID was based on an analytical model that assumed a p-doped perovskite and did not account for the transport layers of the PSC [3, 4]. In this work, we provide an updated interpretation of TID, also accounting for low doping densities in the perovskite, and show what it can teach us about the activation energy, diffusion coefficient, and density of mobile ions.