Improved Perovskite/Carbon Interface through Hot-Pressing: A Case Study for CsPbBr₃-Based Perovskite Solar Cells

Due to the low cost and printable nature of the carbon paste, carbon-based perovskite solar cells (PSCs) are attractive for real application. However, the poor contact at the perovskite/carbon interface obviously hinders the achievable fill factor of the carbon-based PSCs. In this work, we introduce a pressure-assisted method to improve the contact at the perovskite/carbon interface. Via modulating the applied pressure, the power conversion efficiency of CsPbBr3 PSCs (small area) can be improved from the initial 7.40% to 7.95% (pressing) and 8.34% (hot-pressing). A more remarkable feature is that the hot-pressing process boosted the performance from 5.1% (normal) to 6.9% (hot-pressing assisted) of large-scale (0.5 cm2) devices, a more than 30% enhancement. Finally, the hot-pressing method introduced in this work shows great prospects for improving the efficiency of carbon-based PSCs, especially large-scale PSCs.