[20p-211A-1~18] 13.6 Nanostructures, quantum phenomena, and nano quantum devices

[20p-211A-5] Temperature dependence of energy transfer dynamics between semiconductor quantum dots II

〇Yongshin Lee¹, Hisaaki Nishimura¹, Kim DaeGwi¹ (1.Osaka City Univ.)

Keywords:quantum dots, energy transfer, CdS

We have investigated the temperature dependence of energy transfer dynamics between CdS quantum dots (QDs). A bilayer structure consisting of different size CdS QDs was prepared by Layer-by-layer (LBL) method. The energy transfer rate gradually decreases with an increase in temperature. It indicates that the dark exciton state contributes to the photoluminescence (PL) process even at room temperature, reflecting that the bright-dark splitting energy in the donor QDs is larger than the thermal energy at room temperature. Consequently, the energy transfer rate is very small at room temperature. We will quantitatively discuss these experimental results based on the three-level model that takes into account a ground-state and two excited states: a lower lying bound-exciton state and a higher-lying dark-exciton state.