Controlling the size of colloidal nanocrystals is essential to optimizing their performance in optoelectronic devices, catalysis, and imaging applications. Traditional synthetic methods control size by terminating the growth, an approach that limits the reaction yield and causes batch-to-batch variability. I will describe the development of libraries of substituted thiourea and selenourea compounds whose substitution pattern tunes their conversion reactivity over many orders of magnitude. The faster precursor conversion kinetics increases the extent of crystal nucleation, thereby enabling rational control over nanocrystal concentration and thus crystal size at full conversion. Interestingly, nuclei concentration is not linearly dependent on precursor conversion rate as predicted by Sugimoto’s mass-balance model of crystal nucleation and growth. Controlled precursor reactivity and quantitative conversion improve the batch-to-batch consistency of the final nanocrystal size at industrially relevant reaction scales.

Using precursors to control nanomaterial synthesis: Tunable libraries of thiourea and selenourea precursors for metal chalcogenide nanocrystals

254th National Meeting (2017)

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