One‐Step Inkjet Printed Perovskite in Air for Efficient Light Harvesting

Solution‐processed metal‐halide perovskites have demonstrated immense potential in photovoltaic applications. Inkjet printing is a facile scalable approach to fabricate large‐area perovskite solar cells (PSCs) due to its cost‐effectiveness and near unity material utilization ratio. However, controlling crystallinity of the perovskite during the inkjet printing remains a challenge. The PSCs deposited by inkjet printing typically have much lower power conversion efficiencies (PCEs) than those by spin‐coating. Here, we show that high‐quality perovskite films could be inkjet‐printed with an innovative vacuum‐assisted thermal annealing post‐treatment and optimized solvent composition. High‐performance PSCs based on printed CH 3 NH 3 PbI 3 with a PCE of 17.04% for 0.04 cm 2 (13.27% for 4.0 cm 2 ) and negligible hysteresis (lower than 1.0%) are demonstrated. These efficiencies are much higher than the previously reported ones using inkjet‐printing (≤12.3% for 0.04 cm 2 ). The inkjet printing combined with vacuum‐assisted thermal annealing could be an effective low‐cost approach to fabricate high‐performance perovskite optoelectronic thin film devices (including solar cells, lasers, photodetectors, and light‐emitting diodes) with high‐volume production.