Amplified Spontaneous Emission and Lasing from Zn-Processed AgIn5S8 Core/Shell Quantum Dots

I-III-VI ternary quantum dots (QDs) have emerged as favorable alternatives to the toxic II-VI QDs for optoelectronic and biological applications. However, their use as optical gain media for microlasers is still limited by a low neous emission (ASE) and lasing from colloidal QDs of Znprocessed AgIn5S8 (AIS) for the first time. The passivation treatment on the AIS QDs yields a 3.4-fold enhancement of fluorescence quantum efficiency and a 30% increase in the twophoton absorption cross section. ASE is achieved from the AIS/ ZnS core/shell QD films under both one- and two-photon pumping with a threshold fluence of -,84.5 mu J/cm2 and 3.1 mJ/cm2, respectively. These thresholds are comparable to the best optical gain performance of Cd based-QDs reported in the literature. Moreover, we demonstrate a facile whispering-gallery-mode microlaser of the core/shell QDs with a lasing threshold of -,233 mu J/cm2. The passivated AIS QDs can be promising optical gain media for photonic applications.