Phys.org  November 29, 2019 Colloidal quantum dots (CQDs) are highly promising materials for light amplification. But band-edge state degeneracy demands multiple excitons to achieve population inversion increasing the lasing threshold and limits the gain lifetime. Researchers in Singapore have demonstrated that the amplified spontaneous emission (ASE) threshold is controllable in a device where CQD film is exposed to an external electric field. Specifically, singly charged CQDs lower the threshold due to the preexisting electron in the conduction band, while strongly enhanced Auger recombination in doubly charged CQDs stymies the ASE. According to the researchers the next big challenge in laser […]