Doping Location-Dependent Energy Transfer Dynamics in Mn-Doped CdS/ZnS Nanocrystals
2011; American Chemical Society; Volume: 6; Issue: 1 Linguagem: Inglês
10.1021/nn204452e
ISSN1936-086X
AutoresHsiang‐Yun Chen, Sourav Maiti, Dong Hee Son,
Tópico(s)Semiconductor materials and interfaces
ResumoDynamics of energy transfer and charge carrier localization in Mn-doped CdS/ZnS core/shell nanocrystals correlated with doping location and concentration are studied via transient absorption measurement of exciton relaxation dynamics. The strong dependence of exciton-Mn energy transfer rate on doping location was directly resolved in the transient bleach recovery and electron intraband absorption data by using layer-by-layer synthesized Mn-doped nanocrystals. With 1.2 nm decrease in doping radius in the ZnS shell, energy transfer rate increases by 6 fold. We identified that hole trapping is the major competing process that inhibits the energy transfer in Mn-doped CdS/ZnS nanocrystals. From the branching ratio of the energy transfer and hole trapping, combined with luminescence quantum yield measurement, we also obtained doping location-dependent radiative relaxation quantum yield of Mn(2+) ions that is as high as 0.95.
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