Xu Zihao, Jin Tao, Huang Yiming, Mulla Karimulla, Evangelista Francesco A, Egap Eilaf, Lian Tianquan
Department of Chemistry , Emory University , 1515 Dickey Dr , Atlanta , GA 30322 , USA . Email:
Department of Materials Science and NanoEngineering , Department of Chemical and Biomolecular Engineering , Rice University , 6100 Main St , Houston , TX 77005 , USA . Email:
Chem Sci. 2019 May 13;10(24):6120-6124. doi: 10.1039/c9sc01648a. eCollection 2019 Jun 28.
Effective sensitization of triplet states is essential to many applications, including triplet-triplet annihilation based photon upconversion schemes. This work demonstrates successful triplet sensitization of a CdSe quantum dot (QD)-bound oligothiophene carboxylic acid (T6). Transient absorption spectroscopy provides direct evidence of Dexter-type triplet energy transfer from the QD to the acceptor without populating the singlet excited state or charge transfer intermediates. Analysis of T6 concentration dependent triplet formation kinetics shows that the intrinsic triplet energy transfer rate in 1 : 1 QD-T6 complexes is 0.077 ns and the apparent transfer rate and efficiency can be improved by increasing the acceptor binding strength. This work demonstrates a new class of triplet acceptor molecules for QD-based upconversion systems that are more stable and tunable than the extensively studied polyacenes.
三重态的有效敏化对于许多应用至关重要，包括基于三重态-三重态湮灭的光子上转换方案。这项工作展示了与CdSe量子点（QD）结合的寡聚噻吩羧酸（T6）成功实现三重态敏化。瞬态吸收光谱直接证明了从量子点到受体的德克斯特型三重态能量转移，而不会填充单重激发态或电荷转移中间体。对T6浓度依赖性三重态形成动力学的分析表明，1:1量子点-T6复合物中的固有三重态能量转移速率为0.077纳秒，通过增加受体结合强度可以提高表观转移速率和效率。这项工作展示了一类新型的用于基于量子点的上转换系统的三重态受体分子，它们比广泛研究的多环芳烃更稳定且可调谐。
