Nanostructured texturing of CH₃NH₃PbI₃ perovskite thin film on flexible substrate for photodetector application

Large-area nanostructured hybrid CH₃NH₃PbI₃ perovskite thin films are fabricated via a direct one-step blade method on nanograting-patterned flexible cyclic olefin copolymer (COC) substrate in ambient condition. The nanostructure of perovskite films can be well controlled with high crystalline quality, revealed by X-ray diffraction (XRD) and photoluminescence (PL) characterization. Flexible photodetectors with nanostructured perovskite thin films demonstrate better performance than their counterparts with flat perovskite films. Numerical modeling of the local energy distribution of incident light reveals the contribution of nanostructures directly textured in perovskite films to the light absorption enhancement. The blade-coated CH₃NH₃PbI₃ photodetector with the nanostructured texturing exhibits a high detectivity of 1.21 × 10⁹ Jones and a responsivity of 0.36 A/W, which are 15% and 47% higher compared with the photodetector with the flat perovskite film, respectively. Our work offers a facile etching-free process that can create high crystalline nanostructured perovskite films for high-performance photodetectors over large-area flexible substrates.