Photoluminescence of Mid-Infrared HgTe Colloidal Quantum Dots

Abstract

The photoluminescence quantum yield of HgTe colloidal quantum dots is measured from 1800 to 6500 cm–1. There is a steep drop to low energy reminiscent of the generic gap law. However, direct evidence of energy transfer to the C–H stretch and overtone vibrations is apparent when temperature tunes the PL wavelength of a given sample through the vibrational resonances. Calculations based on the radiative rate and resonant energy transfer to the ligand vibrations appear to account for much of the quantum yield drop. Power-dependent photoluminescence lifetime measurements on 3.7 nm particles show fast, ∼50 ps, biexciton lifetime similar to other colloidal quantum dot systems of similar sizes.