Efficient short-wave infrared emission by copper-doped InP/ZnSe/ZnS quantum dots and their application for luminescent solar concentrators

InP quantum dots (QDs) have been a major building block of modern display technology due to their high photoluminescence quantum yield (PLQY) in the visible spectrum, superior stability, and eco-friendly composition. However, their applications at short-wave infrared (SWIR) have been hindered by their low efficiency. Here, we report the synthesis of efficient and SWIR-emitting InP QDs by precisely controlling the InP core nucleation using a low-cost ammonia phosphorus precursor, while avoiding size-limiting ZnCl₂ for effective copper doping. Subsequent epitaxial growth of a lattice-matched ZnSe/ZnS multishell enhanced the QD sphericity and surface smoothness and yielded a record PLQY of 66% with an emission peak at 960 nm. When QDs were integrated as the high-refractive-index luminescent core of a liquid waveguide-based luminescent solar concentrator (LSC), the device achieved an optical efficiency of 7.36%. This performance arises from their high PLQY, spectral alignment with the responsivity peak of silicon solar cells, and the optimized core/cladding waveguide structure. These results highlight the potential of InP QDs as a promising nanomaterial for SWIR emission and applications.