Energy transfer process and temperature-dependent photoluminescence of PbS quantum dot-doped glasses

PbS quantum dot (QD)-doped glasses were fabricated through melt-quenching method. After heat treatment schedule, uniform QDs were precipitated in the glasses and near-infrared emission covering 900-1700nm was obtained under excitation. From photoluminescence (PL) spectra and lifetime decay curves, the whole emission band of QD-doped glasses consisted of emission from the 1S-1S state and the trap state. While using excitation with higher energy, the full width at half maximum (FWHM) of QD-doped glasses broadened because smaller QDs were excited. Energy transfer process among QDs was revealed by measuring the lifetime of different emission bands in PL spectrum and the energy transferred from smaller QDs with broader bandgap to bigger QDs with narrow bandgap. Temperature-dependent PL and the corresponding lifetime decay curves of PbS QD-doped glasses were analyzed. Temperature-dependent bandgap structure of PbS QDs was obtained by using density functional theory (DFT) calculations. The results here give deep insight into optical properties of PbS QD-doped glasses and it is beneficial to design and develop high-performance QD-based optoelectronic devices in theory.