Polymer-Enhanced Active Layer Crystallization in Low-Temperature Carbon-Based Perovskite Solar Cells

High-efficiency perovskite solar cells (PSCs) are emerging as a promising next-generation, low-cost, photovoltaic technology. A key advantage of PSCs is their compatibility with diverse manufacturing techniques, enabling the pursuit of low-cost, stable PSCs. Carbon electrodes, known for their scalability, chemical inertness, and ease of processing through screen printing, have recently seen the development of low-temperature carbon electrodes with high conductivity for use in PSCs. However, optimizing low-temperature carbon-based PSCs (LTC-PSCs), particularly improving the interface between the perovskite and carbon electrodes, remains a significant challenge. In this study, poly(3-hexylthiophene-2,5-diyl) (P3HT) was employed as an additive and a hole-transporting layer (HTL) in LTC-PSCs with low-temperature screen-printing carbon electrodes. The incorporation of P3HT in antisolvent improved the perovskite/carbon interface, reducing the defect density of the perovskite layer. This resulted in a significant average power conversion efficiency (PCE) improvement of 11%. The LTC-PSCs achieved a PCE of 10.90% and demonstrated exceptional stability, retaining 90% of initial PCE after 1200 h under ambient air. This research highlights the potential of LTC-PSCs as low-cost strategies for the commercialization of PSCs.