Tuning Hot Carrier Dynamics of InP/ZnSe/ZnS Quantum Dots by Shell Morphology Control.

ABSTRACT

Isotropic InP/ZnSe/ZnS quantum dots (QDs) are prepared at a high reaction temperature, which facilitates ZnSe shell growth on random facets of the InP core. Fast crystal growth enables stacking faults elimination, which induces anisotropic growth, and as a result, improves the photoluminescence (PL) quantum yield by nearly 20%. Herein, the effect of the QD morphology on photophysical properties is investigated by observing the PL blinking and ultrafast charge carrier dynamics. It is found that hot hole trapping is considerably suppressed in isotropic InP QDs, indicating that the stacking faults in the anisotropic InP/ZnSe structures act as defects for luminescence. These results highlight the importance of understanding the correlation between QD shapes and hot carrier dynamics, and present a way to design highly luminescent QDs for further promising display applications.