Figure 5.

(a) A schematic depiction of a core/shell CdSe/CdS QD (left) and its band diagram (right). (b) Same for a CdSe/CdSe_xS_1–x/CdS QD with an alloyed CdSe_xS_1–x interlayer (1-step alloying). (c) A core/alloy/shell CdSe/CdSe_xS_1–x/CdS QD (left) wherein an alloyed interlayer comprises 3 (left) and 5 (right) layers with different Se-to-S ratios, which leads to a progressively more gradual change of the confinement potential. (d) The increase in the number of alloying steps leads to the increased biexciton emission quantum yield (q_XX) indicating more complete suppression of Auger decay. The black, blue, orange, and green symbols are data points obtained using single-dot measurements. The black line is a guide for the eye which describes the dependence of the average biexciton emission quantum yields (red symbols) on effective exciton volume. The gray line is the trend expected for traditional V-scaling of Auger lifetimes. Considerable deviation between the black and the gray lines which increases with the number of alloying steps indicates the increasing degree of Auger-decay suppression. Adapted with permission from ref (57). Copyright 2014 American Chemical Society.