Exciton Dynamic in Pyramidal InP/ZnSe Quantum Dots for Luminescent Solar Concentrators

Colloidal indium phosphide (InP) quantum dots (QDs) have attracted a great attention for their excellent optical properties, and they are a promising candidate for potential applications in optoelectronic devices, such as photocatalysis, light emitting diodes, and bioimaging. However, their use for luminescent solar concentrators (LSCs) has been limited owing to their low optical efficiency, which is because of the energy loss due to the strong overlap between their emission and absorption spectra. Here, we synthesized pyramidal InP/ZnSe QDs based on aminophosphine as the phosphorus precursor by adding hydro-fluoric acid to remove the oxides on the InP core surface before the growth of a ZnSe shell. Through researching the exciton dynamic of InP/ZnSe QDs with different shell thicknesses, we found that a thick shell can stabilize the 1Pe energy state of the InP core, thus decreasing the spectral overlap in the overall QDs. As a proof of concept, we demonstrated a highly efficient LSC based on "giant" InP/ZnSe QDs, which exhibited an external optical efficiency of 2.5% and a power conversion efficiency of 2% (5 x 5 x 0.5 cm3) upon simulated sunlight illumination (100 mW/cm2), which is among the best reported LSCs based on InP QDs. Pyramidal "giant" InP/ZnSe QDs hold great potential for the breakthrough development in the field of eco-friendly QD-based LSCs.