Enhanced photoluminescence from CuInS2/ZnS quantum dots: Organic superacid passivation

•Optimization of CuInS2 passivation with bis(trifluoromethane) sulfominide superacid.•Improved photoluminescence quantum yields after CuInS2 superacid treatments.•Enhanced long term photoluminescence stability after CuInS2 superacid treatments. Improvements in CuInS2 photoluminescence is necessary before it can replace cadmium- or lead-based quantum dots. We demonstrate that organic superacid passivation of CuInS2 quantum dots significantly improves photoluminescence, with no significant changes in particle size, composition, or structure. We propose organic superacid passivation reduces surface promoted non-radiative decay.