Chapter 4 - Surface modification of all-inorganic lead halide perovskite nanocrystals

Abstract

Newly emerged all-inorganic lead halide perovskite nanocrystals have shown unprecedented optical properties for a variety of display applications. Their superior optical properties over traditional semiconductor nanocrystals have opened a new paradigm in luminescent materials research. Because of their defect tolerance, the photoluminescent quantum yield of lead halide perovskite nanocrystals can reach near-unity. However, the ionic character of these nanocrystals causes extreme lability, which deteriorates its structural and optical properties. Moreover, the binding ability of surface ligands are quite weak and thus easily desorb during conventional purification techniques. Despite this, the use of novel metallo-organic ligands and posttreatment or in situ surface modification processes using several organic and inorganic compounds have shown promising results in achieving excellent optical properties in the case of perovskite nanocrystals. The active role of these additives and ligands should be studied to further explore the salient role of perovskite nanocrystals as functional building blocks for the fabrication of optoelectronic devices. This chapter highlights the typical surface chemistry, potential surface modification, and posttreatment processes used to enhance the optical properties of all-inorganic lead halide perovskite nanocrystals in solution as well as in films. The unique surface chemistry of all-inorganic lead halide perovskite nanocrystals is discussed with respect to the surface modification processes under different conditions.