The Polymer Society of Korea

Abstract

Colloidal quantum dots (QDs) represent a versatile class of solution-processable nanomaterials with tunable emission and high quantum yields. However, their practical application in light amplification has been limited by fast optical gain decay due to nonradiative Auger recombination, especially in dilute, solution-phase environments. Here, we introduce type-(I+II) QDs that create hybrid biexciton gain states composed of direct and indirect excitons. These trion-like states exhibit strongly suppressed Auger decay, resulting in extended optical gain lifetimes of several nanoseconds. When integrated into a Littrow cavity, static liquid solutions of these QDs exhibit stable, narrow-linewidth lasing (<0.4 meV) over a widely tunable spectral range. Beyond solution-phase operation, these colloidal QDs can be integrated into soft material platforms, expanding their applicability as tunable, flexible gain media and potential replacements for dye-based lasers.