Two-dimensional lead-free halide perovskite materials and devices

Two-dimensional (2D) organic-inorganic halide perovskite materials have favorable stability and unique photoelectric properties in comparison with three-dimensional (3D) counterparts and have become a new topic in the field of materials. However, the environmental toxicity of lead is still a major obstacle to their commercialization. In this regard, 2D lead-free halide perovskites come into being and will be the main concern for future commercial applications. Here, we first introduce the synthesis strategies, crystal structure and basic optoelectronic properties of 2D lead-free halide perovskite materials. Subsequently, the application status of solar cells and light-emitting diodes in recent years is summarized. Finally, the existing problems and future development prospects of these kinds of materials are discussed, which provide a reference for the design and preparation of high-performance 2D lead-free halide perovskite optoelectronic devices.