Semiconductor quantum dots (QDs) exhibit unique properties including high absorbance cross section, broad excitation spectrum, tunable emission profile, high photoluminescence quantum yields (PL QYs) and superior photo-chemical/physical stabilities. Fabrication of quantum dots (QDs) with narrow emission covering a wide spectral region has been persistently intriguing due to their potentials in a range of practical applications such as biological labelling and imaging, solar cells, light-emitting diodes (LEDs) and next generation displays. We report a synthesis of CdZnSe-CdZnS core-shell alloy QDs through a Cu-catalyzed solid solution alloying strategy starting from CdSe-CdS core-shell QDs. The resulting CdZnSe-CdZnS alloy QDs exhibit emission profiles covering a wide wavelength range of 470-650 nm while maintaining high PLQYs. In addition, high morphological uniformity of the starting CdSe-CdS QDs can be largely retained in the final alloy QDs. The alloying process is attributed to the high mobility nature of Cu cation in Cd-chalcogenide crystals at elevated reaction temperature, which allows Cu cation act as a transporting agent to transfer Zn component into CdSe-CdS QDs while maintaining the particle integrity. This unique alloying strategy is independent of the shape of starting QDs and can be also applied to the synthesis of CdZnSe-CdZnS nanorods. We anticipate our study will instigate synthesis of various high-quality alloy QDs and other alloy nanocrystals beyond what currently can be achieved.

Cu-catalyzed synthesis of CdZnSe-CdZnS alloy quantum dots with highly tunable emission

2019 Fall National Meeting

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