Temperature-dependent photoluminescent behavior of InP/ZnS quantum dots based on size effects

Abstract InP/ZnS quantum dots (QDs) were synthesized via the thermal injection method and characterized for their morphology and optical properties. The absorption spectrum exhibited a red shift from 380 to 450 nm due to size differences. Photoluminescence (PL) emission varied at 520, 550, 580, and 610 nm, with an 85 nm red shift and varying full width at half maximum. Single-photon excitations are identified in pump-dependent PL spectra. Using a variable temperature fluorescence spectroscopy system, PL behaviors were analyzed, revealing changes in exciton binding energies and phonon energies as temperature increased. The PL peak position initially blue shifted then red shifted due to thermal expansion and electron–phonon interactions. Time-resolved PL at different wavelengths showed varying decay lifetimes, indicating size distribution irregularities in the InP/ZnS QDs.