Beyond quantum dot LEDs: Optical gain and laser action in red, green, and blue colors

State-of-the-art colloidal quantum dots (CQDs) exhibit excellent properties as pure color red, green, and blue (RGB) phosphors for light-emitting applications ranging from solid-state lighting to flat panel displays. Progress in controlling the chemical synthesis of II-VI semiconductor nanocrystals has enabled a better understanding of the fundamental physical processes that dictate their interactions with light at the quantum level. In this article, we review recent work that extends this understanding and the corresponding utility to a higher excitation regime, where optical gain and laser action have been demonstrated across the RGB color spectrum from a single material. Recent developments have surmounted some fundamental challenges to CQDs for optical gain and have made gains toward their possible future as full-color palette lasers.