A new insight into the fabrication of colloidal isotropic ZnO nanocrystals by an organometallic approach

Abstract

The study of factors controlling nanocrystal (NC) growth is essential for uncovering and understanding nanomaterial formation, which typically involves a complex sequence of precursor reactions, nucleation, and growth processes. Herein, as part of the continuous development of the self-supporting organometallic approach for the preparation of quantum-sized colloidal zinc oxide (ZnO) NCs, we selected a series of [EtZn(X)]-type carboxylate precursors, where X = methoxyacetate, 2-(2-methoxyethoxy)acetate, or 2-[2-(2-methoxyethoxy)ethoxy]acetate, as model self-supporting systems with varying carboxylate tail lengths. The controlled exposure of a [EtZn(X)]-type precursor solution to air afforded colloidal ZnO NCs with a narrow unimodal size distribution and coated with strongly anchored X-type ligands. Employing optical spectroscopy techniques, we investigate how the growth dynamics of NCs depend on the length of the carboxylate tail. Moreover, leveraging analytical ultracentrifugation (AUC), we meticulously examined the behavior of NCs in solution under centrifugal forces to gain valuable insights into their stability and aggregation tendencies. This study not only enhances understanding of the underlying ‘living growth’ of organometallic-derived nanostructures that leads to the formation of thermodynamically stable and monodispersed ZnO NCs but also significantly contributes to the ongoing development of more effective methods for synthesizing colloidal ZnO NCs, thereby advancing the field of materials science.