Van Uffelen, Mandy Van Overeem, Baldur Brynjarsson, N.R.M. We show that these shallow trap states are removed when additional wide band gap ZnS shells are grown around the CdSe/CdS core/shell QDs.Ĭhemistry of Materials, 31 (20), 8484-8493 Part of collection We suggest that these shallow trap states reduce the quantum yield because of enhanced hole trapping when the Fermi level is raised electrochemically. This points in the direction of shallow trap states localized on the CdS shell surface that give rise to nonradiative recombination pathways.
By correlating the differential absorbance and the photoluminescence upon electrochemically raising the Fermi level, we reveal that trap states near the conduction band (CB) edge give rise to nonradiative recombination pathways regardless of the CdS shell thickness, evidenced by quenching of the photoluminescence before the CB edge is populated with electrons. In this work, we systematically study the spectroelectrochemical response of CdSe quantum dots (QDs), CdSe/CdS core/shell QDs with varying CdS shell thicknesses, and CdSe/CdS/ZnS core/shell/shell QDs in order to elucidate the influence of localized surface trap states on the optoelectronic properties. (TU Delft ChemE/Opto-electronic Materials) (TU Delft ChemE/Opto-electronic Materials) The deposition of a suitable semiconducting shell on the CdS particles removed the trapping states and signi cantly improved the emission.52 The core.
revealing that modulation doping can passivate interfacial trap states. Electrochemical Modulation of the Photophysics of Surface-Localized Trap States in Core/Shell/(Shell) Quantum Dot Films Modulation Doping of GaAs/AlGaAs Core-Shell Nanowires With Effective Defect.
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