2010 Fiscal Year Final Research Report
Control of energy transfer processes between semiconductor quantum dots
| Project/Area Number |
20560012
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied materials science/Crystal engineering
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| Research Institution | Osaka City University |
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Principal Investigator |
KIM Daegwi Osaka City University, 大学院・工学研究科, 准教授 (00295685)
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| Project Period (FY) |
2008 – 2010
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| Keywords | 応用物性 / 結晶工学 |
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| Research Abstract |
We have investigated energy transfer (ET) mechanism in colloidal QDs measuring photoluminescence dynamics of a bilayer structure consisting of differently sized QDs. In the bilayer structure, the distance between the monolayer of donor QDs and that of acceptor QDs was controlled precisely by a spacer layer that is layer-by-layer assembly of polyelectrolytes. It is demonstrated that ET between the donor and acceptor QDs is conclusively dominated by the dipole-dipole interaction. The temperature dependence of the observed ET rate can be classified into two categories. Under the condition that the thermal energy is comparable to the splitting energy between the bright- and dark-exciton states and above, the observed ET rate is dominated by the thermal population behavior of the bright-exciton state : the ET rate increases with an increase in temperature. On the other hand, in the lower temperature region, the observed ET rate is almost constant, which may be due to a breakdown of the thermal equilibrium between the lower-lying dark-exciton state and the bright-exciton state.
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