High-throughput large-area vacuum deposition for high-performance formamidine-based perovskite solar cells†
Vacuum deposition has been investigated for the fabrication of perovskite solar cells (PSCs) in the laboratory, but its efficiency is still significantly lower than using solution deposition. Herein, we report an efficient vacuum deposition approach that is compatible with large-area, high-throughput processing. Excellent uniform and high quality perovskite films have been made on glass (400 cm2) and flexible (300 cm2) substrates. In addition, an in-vacuum low-temperature annealing process is developed to fabricate high-density formamidine-based perovskite films. It is found that the performance of PSCs is severely affected by the in-vacuum annealing temperature. When the annealing temperature is optimized at 60 °C, the efficiency of the resulting PSC is increased to 21.32%, the highest value for a PSC fabricated using vacuum deposition. Thanks to the solvent-free and air-free environment, the PSCs fabricated using the vacuum deposition exhibit excellent long-term stability.