Temperature-Dependent Recombination Processes in Small-Sized PbSe/PbS Core/Shell Colloidal Quantum Dots

Abstract

The work focuses on the optical investigation of temperature-dependent recombination processes in small-sized PbSe/PbS core/shell colloidal quantum dots (CQDs) with core diameter of (2 - 2.5) nm and the shell thickness of (0.5 - 1.0) nm under air-free conditions and after air exposure. These CQDs have a tunable absorption edge around 1 μm and a rather narrow photoluminescence linewidth, their emission recombination process is characterized by the μs timescale and by longer radiative lifetimes in the entire temperature range and especially at low temperatures (a 2.6-fold increase) as compared to the corresponding PbSe samples. The PbSe/PbS core/shell CQDs are oxidation-stable towards time-limited air exposure.