Effect of Transport Layers on Reverse Bias Recovery in Perovskite Solar Cells

• Main Authors: Ahmad, Viqar, White, Thomas P., Catchpole, Kylie R., Weber, Klaus J., Walter, Daniel C.
• Format: Conference Proceeding
• Language: English
• Subjects: Computer architecture; Ions; Microprocessors; Numerical models; Perovskites; Photoconductivity; Photovoltaic cells; Photovoltaic systems; Power conversion; Semiconductor device modeling
• ISSN: 2995-1755
• DOI: 10.1109/PVSC57443.2024.10749605

For perovskite solar cells (PSCs), sufficiently large reverse bias (RB) voltages can induce destructive processes that permanently reduce power conversion efficiency (PCE). However, initial results suggest that appropriate cell architectures and module interconnections may limit RB damage. However, this raises the question of how PSC hysteresis will affect energy output in the period following RB exposure. Although there have been previous reports on the destructive affects of reverse bias on perovskite solar cells, an in-depth study on fully recovering cells, delineating the role of perovskite structure is still missing. This work characterises the full recovery of photocurrent following a step change from RB (in the dark), back to maximum power point (MPP), under illumination. In agreement with our a priori suppositions, we observe that the period of recovery is highly variable and can extend up to 10x the duration of the reverse bias exposure. Furthermore, we find that the speed of RB recovery is not necessarily correlated with forward bias PCE. We correlate recovery characteristics with transport layer selection and observe up to an order-of-magnitude difference in recovery times between cell architectures. Supported by a numerical ionic-electronic device model, we propose three power loss mechanisms that can be amplified by RB ion accumulation. These mechanisms are explained solely by conventional semiconductor electrostatics and do not require secondary reactions driven by reverse bias ion accumulation.