Designing stable lead halide perovskite nanocrystals: From a single particle to nanocomposites

Metal halide perovskite nanocrystals have attracted substantial interest given their easy manufacturing, superior Photoluminiscence Quantum Yield and striking optical properties. Despite the huge potential of such materials, their practical implementation and future technological applications need to overcome stability drawbacks: spontaneous degradation, which is accelerated by external stressors (i.e., moisture, oxygen, heat, light, and their combinations), poor phase stability and loss of their colloidal stability due to ligand lability. Within this framework, the understanding of their surface chemistry features and ligand-binding patterns plays a key role in improving the robustness and stability of perovskite nanocrystals. This review presents a comprehensive study of state-of-the-art and current challenges in surface chemistry, interface engineering and encapsulation methodologies for stabilizing lead halide perovskite nanoparticles. We first introduced lead halide perovskite structural and optical properties and a brief discussion of synthesis methods. Next, we explored recent developments in encapsulation methods in different protective matrices comprising from core-shell to macroscale nanocomposites. We also analyzed the advantages and shortcomings of each approach according to their final applications. Finally, we concluded with a discussion of open research challenges and future directions in the aforementioned aspects.