Controllable printing of large-scale compact perovskite films for flexible photodetectors

Perovskite materials are promising candidates for the next generation of wearable optoelectronics. However, due to uncontrolled crystallization and the natural brittle property of crystals, it remains a great challenge to fabricate large-scale compact and tough perovskite film. Here we report a facile method to print large-scale perovskite films with high quality for flexible photodetectors. By introducing a soluble polyethylene oxide (PEO) layer during the inkjet printing process, the nucleation and crystal growth of perovskite is well controlled. Perovskite films can be easily printed in large scale and patterned in high resolution. Moreover, this method can be extended to various kinds of perovskite materials, such as MAPbI 3 (MA = methylammonium), MA 3 Sb 2 I 9 , and (BA) 2 PbBr 4 (BA = benzylammonium). The printed perovskite films show high quality and excellent mechanical performance. The photodetectors based on the MAPbBr 3 perovskite films show a responsivity up to ∼ 1,036 mA/W and maintain over 96.8% of the initial photocurrent after 15,000 consecutive bending cycles. This strategy provides a facile approach to prepare large-scale flexible perovskite films. It opens up new opportunities for the fabrication of diverse wearable optoelectronic devices.