Temperature-Dependent Photoluminescence of CdSe-Core CdS/CdZnS/ZnS-Multishell Quantum Dots

Citations Over TimeTop 10% of 2009 papers

Abstract

The photoluminescence (PL) spectra of CdSe-core CdS/CdZnS/ZnS-multishell quantum dots (QDs) were studied to understand the radiative and nonradiative relaxation processes in the temperature range from 80 to 360 K. The mechanism of temperature-dependent nonradiative relaxation processes in the CdSe QDs with changing the shell structures was found to evolve from thermal activation of carrier trapping by surface defects/traps in CdSe core QDs to the multiple longitudinal-optical (LO) phonon-assisted thermal escape of carriers in the core/shell QDs. An increase in PL intensity with increasing temperature was clearly observed in the core/shell QDs with a thick CdS monoshell and a CdS/ZnCdS/ZnS multishell. The PL enhancement was considered to come from delocalization of charge carriers localized at the CdSe/CdS interface with the potential depth of ∼30 meV. The experimental results indicated that the improvement of PL quantum efficiency in CdSe-core CdS/CdZnS/ZnS-multishell QDs could be understood in terms of the reduction of nonradiative recombination centers at the interfaces and on the surface of the multishell, as well as the confinement of electrons and holes into the QDs by an outer ZnS shell.

Related Papers

• → La2MgTiO6:Bi3+/Mn4+ photoluminescence materials: Molten salt preparation, Bi3+ → Mn4+ energy transfer and thermostability(2020)21 cited
• → Photoluminescence of porous Si, oxidized then deoxidized chemically(1992)109 cited
• → Forming delocalized intermediate states with realistic quantum dots(2012)9 cited
• → Study of delocalized and localized states in ZnSeO layers with photoluminescence, micro-photoluminescence, and time-resolved photoluminescence(2019)7 cited
• → Ballistic effect and new concept of Si wire photoluminescence(2003)1 cited