Green to the core : Cdx Zn1−x Se alloy core nanocrystals are synthesized and overcoated with Cdy Zn1−y S to create core–shell nanocrystals with the ideal wavelength of emission for quantum dot light‐emitting device (QD‐LED) displays. These (Cdx Zn1−x Se)Cdy Zn1−y S core–shell nanocrystals are used to fabricate color‐saturated green‐emitting QD‐LEDs (see picture), which are suitable for display applications.