Unveiling the Myths of Co-deposition of Hole Conductors and Perovskite Layers: A Mechanistic Study

Perovskite solar cells (PSCs) hold great promise as photovoltaic technology, with power conversion efficiencies exceeding 27%. To further reduce the levelized cost of energy, simplifying PSC manufacturing processes is essential. In this study, we introduce a streamlined one-step solution-coating strategy that simultaneously deposits both the hole-conductor and perovskite layers. We demonstrate that doped self-assembled monolayers (SAMs), containing phosphonic or carboxylic acids, diffuse and spontaneously assemble on both indium tin oxide (ITO) substrates and perovskite surfaces during film formation. This process results in a stable monolayer that functions as an efficient hole-selective contact while promoting favorable perovskite crystallization. Moreover, the incorporation of a functional isolation layer effectively mitigates the side effects induced by perovskite-anchored SAMs, thereby enhancing device efficiency and stability. The resulting PSCs exhibit a remarkable power conversion efficiency of 25.1% and maintain over 85% of their initial performance after 1000 hours of maximum power point tracking under continuous illumination.