The size and shape dependent photophysical properties of semiconductor nanocrystals make them essential components in the fabrication of light-emitting diodes, photovoltaic cells, and lasers. Recently, studies have focused on understanding the mechanism of formation of active nuclei, which then undergo nucleation and growth processes to produce well-defined nanocrystals. However, the growth mechanism of nanocrystal formation from the active nuclei is still not fully understood.   Here we report a time-resolved study using optical spectroscopy, mass spectrometry, X-ray diffraction, and other surface characterizations to deconvolute the complete growth mechanism of ultra-small metal chalcogenide nanocrystals. For the first time, we have observed the transition from broad emission to a combination of band edge and deep trap emission during the formation of nanocrystals, which is due to the continuous passivation of the nanocrystal surface by ligands. Our understanding of the growth process of nanocrystals will allow the design of appropriate synthetic methodology to control their size, shape, and composition, which will further enhance the efficiency of future photovoltaic and light-emitting devices.

Real-time monitoring of the growth of ultrasmall semiconductor nanocrystals

246th National Meeting (2013)

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