Precise Engineering of Nanocrystal Shells via Colloidal\nAtomic Layer Deposition

Abstract

We\npresent a general strategy for a facile synthesis of complex\nmultifunctional nanoscale materials via colloidal atomic layer deposition\n(c-ALD). The c-ALD technique is based on self-limiting half-reactions\nof ionic precursors on the surface of a nanocrystal (NC) occurring\nat room temperature. Using this technique, uniform layers of CdS and\nZnS semiconductor shells were epitaxially grown on CdSe semiconductor\ncores with different shell combinations, leading to the precise control\nof the optical properties of these heterostructures. All core–shell\nmulticomponent nanoparticles preserve narrow size distributions, phase\ncrystallinity, and shape homogeneity of the initial NCs. Furthermore,\nwe attempted to extend the toolbox of the c-ALD to combine materials\nwith intrinsically different properties, such as Au/CdS core/shell\nstructures with substantial lattice mismatch. The results presented\nin this work demonstrate great opportunities for creating functional\nmaterials with programmable properties for electronics and optoelectronics.