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

摘要

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 time-scale 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.