Bright State Sensitized Triplet Energy Transfer from Quantum Dot to Molecular Acceptor Revealed by Temperature Dependent Energy Transfer Dynamics
Bright State Sensitized Triplet Energy Transfer from Quantum Dot to Molecular Acceptor Revealed by Temperature Dependent Energy Transfer Dynamics
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DOI：
10.1021/acs.nanolett.2c00017
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发表时间：
2022-05-25
期刊：
影响因子：
10.8
通讯作者：
Lian, Tianquan
中科院分区：
文献类型：
--
作者：
Jin, Tao;He, Sheng;Lian, Tianquan
量子点（QD）敏化分子三重态激发态产生是传统三重态收获方案的一种有前途的替代方案。然而，量子点亮/暗态与量子点敏化三重态能量转移（TET）之间的关系尚不清楚。本文以CdSe/CdS核壳qd -寡硫吩为模型体系，研究了亮/暗态对TET的贡献。通过改变温度调节量子点明暗态之间的平衡，并利用瞬态吸收光谱监测TET动态。受体三重态激发态生长动力学分析表明，在5k时，亮态和暗态的TET生长速率分别为0.492 +/- 0.011 ns（-1）和0.0271 +/- 0.0014 ns(-1)，表明亮态对TET有显著贡献。结果被具有相同电子/空穴自旋投影的亮态波函数分量合理化，导致TET概率非零。该研究为量子点致敏TET机制提供了新的见解，并为未来通过量子点激子工程优化TET效率提供了启示。
Quantum dot (QD) sensitized molecular triplet excited state generation has been a promising alternative for traditional triplet state harvesting schemes. However, the correlation between QD bright/dark states and QD sensitized triplet energy transfer (TET) has been unclear. Herein, we studied the bright/dark states contribution to TET with CdSe/CdS core/shell QD-oligothiophene as the model system. Equilibrium between QD bright and dark states was tuned by changing temperature, and TET dynamics were monitored with transient absorption spectroscopy. Analysis of acceptor triplet excited state growth kinetics yields rates of TET from bright and dark states as 0.492 +/- 0.011 ns(-1) and 0.0271 +/- 0.0014 ns(-1) at 5 K, suggesting significant contribution of bright states to TET. The result was rationalized by bright state wave function components with the same electron/hole spin projections leading to nonzero TET probability. The study provides new insights into QD sensitized TET mechanisms and inspiration for future TET efficiency optimization through QD exciton engineering.