Methylamine-Based Method to Deposit MAPbI3 Nanoscale-Thick Films for Efficient Perovskite Solar Cells with Carbon Electrodes

Low-temperature-derived carbon-based hole transport layer (HTL)-free perovskite solar cells (PSCs) have garnered considerable interest due to their numerous advantages. However, the power conversion efficiency (PCE) remains significantly lower than those of state-of-the-art PSCs using conventional organic HTLs and noble metal electrodes. Herein, we report a method to deposit MAPbI3 films in an ambient environment with precise morphology control, which exhibit large grains with highly preferential growth orientation vertical to the substrate, greatly enhancing the transportation of the carriers along the vertical direction and decreasing the carriers' recombination. As a result, the low-temperature processed PSCs with a simple configuration of ITO/SnO2/MAPbI3/carbon exhibit a superior PCE of 15.62% accompanied by an open-circuit voltage (Voc) of 1.021 V. This feasible method can be further extended to large-scale fabrication of fully printed, cost-effective, low-temperature carbon-based HTL-free PSCs.