Thermally Activated Photoluminescence in Lead Selenide Colloidal Quantum Dots
Authors:
Abstract
The thermal activation processes in PbSe colloidal quantum dots and their influence on the ground‐state exciton emission are discussed. Activation of a dark exciton occurs at 1.4–7 K, assisted by an acoustic phonon coupling. Activation of a bright exciton occurs at 100–200 K, which appears as a sudden change in the photoluminescence band intensity, energy, and full width at half maximum. This activation overcomes the dark–bright‐state splitting, when the activation temperature increases with the decrease of the dots' size. The dark exciton lifetime is found to be ≈6–12 µs at 1.4 K, while the bright exciton lifetime at 300 K evaluated as 450 ns varies slightly with the change in the size of the dots. In addition, the emission quantum yield of these dots, measured at a variety of temperatures when dissolved in various solvents, reveals information about the influence of the environment on the recombination processes.Keywords
This publication has 41 references indexed in Scilit:
- Utilizing the Lability of Lead Selenide to Produce Heterostructured Nanocrystals with Bright, Stable Infrared EmissionJournal of the American Chemical Society, 2008
- IV–VI Nanocrystal–polymer solar cellsJournal of Photochemistry and Photobiology A: Chemistry, 2008
- Optical Investigation of Quantum Confinement in PbSe Nanocrystals at Different Points in the Brillouin ZoneSmall, 2008
- The Excitonic Exchange Splitting and Radiative Lifetime in PbSe Quantum DotsNano Letters, 2007
- Hierarchical Conjugate Structure of γ-Fe2O3 Nanoparticles and PbSe Quantum Dots for Biological ApplicationsThe Journal of Physical Chemistry C, 2007
- Shape Control of PbSe Nanocrystals Using Noble Metal Seed ParticlesNano Letters, 2006
- Raman study of phonon modes and disorder effects in Pb1−xSrxSe alloys grown by molecular beam epitaxyJournal of Applied Physics, 2006
- Confinement effects in PbSe quantum wells and nanocrystalsPhysical Review B, 2004
- Tunable Near-Infrared Optical Gain and Amplified Spontaneous Emission Using PbSe NanocrystalsThe Journal of Physical Chemistry B, 2003
- Temperature dependence of the energy gap in semiconductorsPhysica, 1967