Absolute Photoluminescence Quantum Yields of IR-26 Dye, PbS, and PbSe Quantum Dots

In this study, we have directly measured the photoluminescence quantum yield (Phi(PL)) of 1R-26 at a range of concentrations and the Phi(PL), of PbS and PbSe QDs for a range of sizes. We find that the Phi(PL) of IR-26 has a weak concentration dependence due to reabsorption, with a Phi(PL) of 0 048 +/- 0.002% for low concentrations, lower than previous reports by a full order of magnitude. We also find that there is a dramatic size dependence for both PbS and PbSe QDs. with the smallest dots exhibiting a Phi(PL) in excess of 60%, while larger dots fall below 3% A model, including nonradiative transition between electronic states and energy transfer to ligand vibrations, appears to explain this size dependence These 20 findings provide both a better characterization of photoluminescence for near-