Doping Location-Dependent Energy Transfer Dynamics in Mn-Doped CdS/ZnS Nanocrystals

作者：Chen Hsiang Yun; Maiti Sourav; Son Dong Hee^*

来源：ACS Nano, 2012, 6(1): 583-591.

DOI：10.1021/nn204452e

• doped semiconductor nanocrystals
• energy transfer
• transient absorption
• luminescence quantum yield
• exciton dynamics

Dynamics 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 Mn2+ ions that is as high as 0.95.

• 出版日期2012-1