Proceedings of International Conference on Hybrid and Organic Photovoltaics (HOPV23)
Publication date: 30th March 2023
Perovskite solar cells (PSC) are a promising technology with the potential to further advance the photovoltaic industry. Currently, a vast majority of PSCs are fabricated using silver or gold as the top electrode. However, chemical reactions of these electrode materials with and diffusion in perovskite layer have been shown to affect long-term stability through degradation. In addition, the cost of using expensive elements such as gold raises concerns about cost-effective large-scale fabrication. Possible candidates for low-cost, stable, and scalable alternatives are carbon-based materials. In this work, we show how a buffer of vapour-deposited chromium or bismuth metal nanolayers is necessary for the solution-processing of carbon pastes in inverted devices, and ensuring an improved ohmic contact between a carbon-based electrode and the electron transport layer. Despite improved photovoltaic performance in each bilayer case, we find the long-term stability of bismuth-carbon-based devices to be poor, whilst devices utilising a chromium-carbon bilayer show higher stability under certain aging conditions compared to the chromium-gold reference cell. Our work highlights how bilayers can pave the way to cheaper and more stable electrode configurations for perovskite solar cells.