Emerging two-dimensional halide perovskite nanomaterials

Halide-based perovskites have been found to be promising semiconductor materials for a variety of electronic and optoelectronic devices with high performance, including solar cells, light emitting diodes, photodetectors, etc. An ultra-long charge carrier lifetime/diffusion length, a high photoluminescence quantum efficiency, and a defect tolerant nature are essential in achieving high efficiency devices. Fundamental understanding of the structure-property-performance relationship of the halide perovskite at the nanoscale is currently attracting a significant amount of interest. In particular, an important and urgent topic is to bring the halide perovskites into the two-dimensional (2D) materials family not only for device miniaturization but also for exploring their physical properties under quantum confinement. Here, we highlight recent breakthroughs in the synthesis, characterization, and device application of atomically thin 2D halide perovskites. Moreover, future directions and challenges will be discussed to shed light on this promising field.