Photovoltaic Performance Improvement in Vacuum-Assisted Meniscus Printed Triple-Cation Mixed-Halide Perovskite Films by Surfactant Engineering

Scalable coating methods have recently emerged as practical alternative deposition techniques to the conventional spin-coating despite their lower yielding power conversion efficiencies (PCEs). The most important barrier acting against the use of scalable deposition methods to get a highly absorbing (>95%) film with controlled morphology in the high crystallinity of perovskite particles is the impossibility of antisolvent dripping during the deposition. Here, we demonstrate the positive role of both the surfactant-engineering and the vacuum-annealing (<100 Pa) process in improving the device performance to overcome this limit. A detailed optimization of the vacuum-assisted meniscus printing parameters is discussed to get a pinhole-free triple-cation mixed-halide perovskite layer with high crystallinity. In particular, the results showed that with the increase in surface coverage, wettability and perovskite crystallinity were achieved by adding Triton X-100 (12.5 mM) as a surfactant into the precursor solution. The perovskite devices with the optimized precursor ink formula and optimized meniscus printing parameters showed a PCE of 15.1 and 12.3 with the active area of 0.09 cm(2) and 1 cm(2), respectively. Consequently, the obtained results suggested that perovskite cells made by this vacuum-assisted printing technique and the precursor system could lead to the improved device performance and reproducibility in a high humidity (70-90%) environment.