Contents I. Introduction
Colloidal quantum dots are attractive fluorescent materials because of their ability to emit full color spectrum by tuning their size in a simple synthesis procedure [1]. Their use at low excitation as luminescent media is well established due to high quantum efficiency and stability. But, at higher excitation levels for achieving population inversion for a laser, earlier work has found that when generating more than one electron hole pair (exciton) per CQD, the radiative efficiency drops dramatically because of enhanced non-radiative multiexciton Auger recombination in the 0-dimensional quantum confined system [2]. This has been a challenging problem for over a decade: how to extend such CQDs to laser applications when relying on optical amplification from bi-exciton states. In the laboratory, the approaches to build up the population inversion quickly have relied on using ultrashort (sub-psec) optical pulse pumping sources to overcome the very fast Auger recombination, typically on the order of hundreds of ps [3]. Such extreme conditions are impractical for any compact device applications such as, say, RGB projector displays.
