A Reactivity-controlled Epitaxial Growth Strategy for Large-sized Nanocrystal Synthesis

Abstract Large-sized ZnSe nanocrystals are expected to emit pure-blue-light between 455-475 nm for display applications, however, haven’t been achieved up to date. By analyzing the influence of the reactivity of Zn and Se precursors, we found that the final size of ZnSe nanocrystals via hot-injection has a critical value that can be varied by ligands or precursors. To describe the key factors in determining the final size of ZnSe nanocrystals, we propose a nuclei number-considered LaMer model based on the Maxwell-Boltzmann distribution of crystal embryos. As a result, a general strategy of reactivity-controlled epitaxial growth (RCEG) was developed to synthesize large-sized ZnSe nanocrystals through sequential injection of high-reactivity and low-reactivity Zn (Se) precursors. The resulted large-sized ZnSe nanocrystals show pure-blue emission between 455-470 nm. We further fabricated efficient and stable large-sized ZnSe/ZnS core-shell nanocrystals with photoluminescence quantum yields up to 60%. Moreover, the RCEG strategy is versatile to synthesize large-sized CdSe and PbSe nanocrystals with average size over 35 nm. The hybridization of quantum confined effects and classical surface effects in these large-sized semiconductor nanocrystals, which will open up new directions for fundamental research and application explorations.