Fabrication of Printed Mesoscopic Perovskite Solar Cells Based on Nonannealing Strategy Perovskite Film to Achieve PCE > 18%

In printable mesoporous perovskite solar cells (p-MPSCs), the perovskite films deposited from room-temperature solvents can effectively optimize the interface between the perovskite films and the electrodes. However, the low crystallization rate of perovskite thin films at room temperature often leads to the formation of nonphotoactive phases and an increase in the density of defect states. To accelerate the crystallization of perovskite films at room temperature, acetonitrile (ACN) is introduced as a cosolvent in the binary solvent system of 2-methoxyethanol/N-methyl-2-pyrrolidone (2 ME/NMP). The high volatility and excellent wettability of ACN improve the crystallization rate of perovskite films and optimize their crystallinity. Furthermore, the introduction of the multifunctional additive Phenformin hydrochloride in the perovskite precursor solution further optimizes the crystallization process of the perovskite films, passivating deep defects in the perovskite films and forming high-quality perovskite films in the mesopores. The optimized p-MPSCs achieve a power conversion efficiency (PCE) of 18.30%, which is the highest PCE for room temperature perovskite film p-MPSCs. Moreover, the optimized p-MPSCs exhibit negligible hysteresis and excellent reproducibility, showing no significant PCE degradation after being stored in air for over 3000 h.