Kinetic Control for Continuously Tunable Lattice Parameters, Size, and Composition during CsPbX₃ (X = Cl, Br, I) Nanorod Synthesis.

Abstract

The fast kinetics of all-inorganic CsPbX₃ (X = Cl, Br, or I) nanocrystal growth entail that many synthetic strategies for structural control established in other semiconductor systems do not apply. Rather, products are often determined by thermodynamic factors, limiting the range of synthetic outcomes and functionality. In this study, we show how reaction kinetics are significantly slowed if nanocrystals are prepared using a dual injection strategy that moderates the crucial interaction between cesium and halide during nucleation and growth. The result is highly uniform nanorod or cuboid nanocrystals with a controllable size and aspect ratio across the quantum confinement regime, obtainable for both pure and mixed halide compositions. Further, the crystal lattice is continuously tunable between the tetragonal (<i>I</i>4/<i>mcm</i>) and orthorhombic (<i>Pbnm</i>) phases, independent of the overall nanorod morphology, enabling significantly more sophisticated structure-property relationships that can be tailored during this kinetically controlled synthesis.