The unique physical and chemical properties of metal halide perovskites predestine the devices to achieve high performance in optoelectronic field. Among the numerous high qualities of perovskites, their different low-temperature synthesis methods and preparation processes make them impressive and popular materials for flexible optoelectronic devices. Mainstream perovskite devices, for instance, solar cells, photodetectors and light-emitting diodes, have been fabricated on flexible substrates and show outstanding flexibility as well as high performance. For soft wearable electronic systems, mechanical flexibility is the premier condition. Compared to common devices based on rigid substrates, flexible perovskite devices are more practical and see widespread applications in energy, detection, display, and other fields. This review summarizes the recent progress of flexible perovskite solar cells, photodetectors and light-emitting diodes. The design and fabrication of different high-performance flexible perovskite devices are introduced. Various low-dimensional perovskite materials and configurations for flexible perovskite devices are presented. In addition, the limitations and challenges for further application are also briefly discussed.

Despite the considerably improved efficiency of inorganic-organic metal hybrid perovskite solar cells (PSCs), electron transport is still a challenging issue. In this paper, we report the use of ZnO nanorods prepared by hydrothermal self- assembly as the electron transport layer in perovskite solar cells. The efficiency of the perovskite solar cells is significantly enhanced by passivating the interfacial defects via atomic layer deposition of Al₂O₃ monolayers on the ZnO nanorods. By employing the Al₂O₃ monolayers, the average power conversion efficiency of methylammonium lead iodide PSCs was increased from 10.33% to 15.06%, and the highest efficiency obtained was 16.08%. We suggest that the passivation of defects using the atomic layer deposition of monolayers might provide a new pathway for the improvement of all types of PSCs..