On the efficacy of anthracene isomers for triplet transmission from CdSe nanocrystals.
On the efficacy of anthracene isomers for triplet transmission from CdSe nanocrystals.
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DOI：
10.1039/c6cc08229g
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发表时间：
2017-01
影响因子：
4.9
通讯作者：
Pan Xia;Zhiyuan Huang;Xin Li;J. Romero;V. Vullev;G. Pau;M. Tang
中科院分区：
文献类型：
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作者：
Pan Xia;Zhiyuan Huang;Xin Li;J. Romero;V. Vullev;G. Pau;M. Tang
研究了异构体取代对纳米晶体 (NC) 供体和分子受体之间三线态能量转移 (TET) 传递体的影响。每个异构受体预计以相对于 NC 供体的独特方向结合。我们看到这种轨道重叠极大地影响了三联体的传输。这里，两个官能团，即羧酸和二硫代氨基甲酸酯，在蒽环的 1-、2-和 9-位之间变化，得到三种 ACA 和三种 ADTC 异构体。这六种蒽异构体充当 CdSe NC 敏化剂和 9,10-二苯基蒽湮没剂之间三重态的发射体，用于光子上转换。 9-ACA 的光子上转换量子产率 (QY) 最高 (12%)，9-ADTC 最低 (0.1%)，1-ACA 和 1-ADTC 均为 3% 左右，2-异构体约为 1%。这些 QY 趋势反映在超快瞬态吸收光谱给出的 TET 速率中，其中测量到的 9-ACA 的最大值为 3.8 × 107 s-1。测量溶液和聚合物主体中的分子激发态能级，以将结构与 TET 相关联。这项工作证实了蒽激发态水平对分子取代非常敏感，这与轨道重叠相结合，严重影响了基于 Dexter 的 TET。
The effect of isomeric substitutions on the transmitter for triplet energy transfer (TET) between nanocrystal (NC) donor and molecular acceptor is investigated. Each isomeric acceptor is expected to bind in a unique orientation with respect to the NC donor. We see that this orbital overlap drastically affects the transmission of triplets. Here, two functional groups, the carboxylic acid and dithiocarbamate, were varied between the 1-, 2- and 9-positions of the anthracene ring to give three ACA and three ADTC isomers. These six anthracene isomers served as transmitters for triplets between CdSe NC sensitizers and 9,10-diphenylanthracene annihilators for photon upconversion. The photon upconversion quantum yield (QY) is the highest for 9-ACA (12%), lowest for 9-ADTC (0.1%), around 3% for both 1-ACA and 1-ADTC, and about 1% for the 2-isomers. These trends in QYs are reflected in the rates of TET given by ultrafast transient absorption spectroscopy where a maximum of 3.8 × 107 s-1 for 9-ACA was measured. Molecular excited state energy levels were measured both in solution and polymer hosts to correlate structure to TET. This work confirms that anthracene excited states levels are very sensitive to molecular substitution, which in combination with orbital overlap, critically affect Dexter-based TET.