<br/>Luminescent quantum dots have attracted the attention of the nanoscience and nanotechnology community due to their superb luminescence properties including their high absorptivity and emission quantum yield, their narrow, symmetric, and size tunable emission peaks, and their high chemical and photostability. Luminescent semiconductor quantum dots have been studied since the 1980s. However, the toolkit of analytical techniques used to monitor their formation and degradation in solution in real time remained limited. Our study focuses on the use of time correlated single photon counting (TCSPC) fluorescence lifetime spectroscopy for quantitative analysis of luminescent quantum dots during the formation of core and core-shell structures of CdSe and CdSe/ZnS quantum dots and on monitoring their degradation in solution under conditions of elevated temperature, typical to temperature of consumer electronics devices which utilize quantum dots as essential components, and under conditions of oxidative stress typical to biological systems where quantum dots are used as luminescence imaging agents. The fluorescence lifetime measurements combined with complementary luminescence techniques revealed that passivation of quantum dots with a higher energy bandgap shell does increase their stability towards oxidation but the majority of the protective effect is realized with a single monolayer shell coating. Our study also revealed that semiconductor quantum dots are not chemically stable under conditions of elevated temperature. This raises concerns about their applicability in consumer electronics devices and points to the necessity to incorporate mechanisms of effective heat dissipation in these devices.<br/>

Fluorescence lifetime spectroscopy for real time monitoring of the formation and degradation of luminescent quantum dots in solution

254th National Meeting (2017)

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