Abstract: A nanocrystal has a semiconductor core and a semiconductor shell at least partially surrounding the core. The shell includes at least a first discrete layer of a small-bandgap semiconductor that may be an embedded layer of the shell or provided as a capping layer, or both. The small bandgap semiconductor may include one or more Group IV elements. The shell may include multiple discrete layers. The colloidal semiconductor nanocrystals may have one or more of the following advantages: higher quantum efficiency; improved photoluminescence efficiency at room or elevated temperatures or at high optical excitation flux; improved stability; and improved color purity. In certain embodiments, these performance advantages may be achieved without the need for toxic elements such as arsenic and cadmium.

Abstract: Nanocrystals including a III-V class semiconductor core and a II-VI class semiconductor shell that at least partially coats the core, in which the shell includes a magnesium-containing first zone and a magnesium-free buffer zone provided between the core and the first zone. Nanocrystals including a non-homogeneous inner core having a first non-uniform band energy profile, and a non-homogeneous outer core having a second non-uniform band energy profile.