Silicon has become a very popular area of study due to its non-toxicity and semiconductor properties and to replace more toxic semiconducting nanocrystals like cadmium and lead chalcogenides. The most promising route known is the high temperature disproportionation of hydrogen silsesquioxane (HSQ) because it offers high crystallinity, precise control over nanocrystal size, and high photoluminescence. However, expensive, specialized equipment is needed to withstand temperatures over 1100°C which are needed produce nanocrystals over 5 nm. This problem can be overcome by utilizing β-tin to act as a catalyst and reduce the annealing temperature while maintaining control over the size and retaining crystallinity. Due to physical and chemical differences in silicon and tin, tin can be easily removed during the synthetic process to obtain pure silicon nanocrystals. When HSQ is synthesized, β-tin can be homogenously distributed via a soluble tin precursor. As HSQ disproportionates under heat, the tin precursor is reduced in situ to β-tin. The tin can then form seeds in the resultant silica matrix to catalyze the decomposition of silane and reduce the time and temperature needed for annealing. Tin can then be removed during the liberation of silicon nanocrystals via hydrofluoric acid etching and hydrosilylation is performed to afford passivated, colloidally stable silicon nanocrystals. Herein, we will discuss the effects of HSQ and the resultant nanocrystals produced with and without β-tin on nanocrystal size, morphology, crystallinity, ligand exchange efficiency, absorption, energy gap, and photoluminescence.

Influence of in-situ tin catalyst on size and crystallinity of silicon nanocrystals produced via high temperature synthesis

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.