时间分辨荧光研究通过限制分子内电荷转移态增强聚集诱导发光。
Time-resolved fluorescence study of aggregation-induced emission enhancement by restriction of intramolecular charge transfer state.
机构信息
State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China.
出版信息
J Phys Chem B. 2010 Jan 14;114(1):128-34. doi: 10.1021/jp909063d.
Cyano-substituted oligo (alpha-phenylenevinylene)-1,4-bis(R-cyano-4-diphenylaminostyryl)-2,5-diphenylbenzene (CNDPASDB) molecules are studied in solution and aggregate state by time-resolved fluorescence techniques. CNDPASDB exhibits a strong solvent polarity dependent characteristic of aggregation-induced emission (AIE). By time-dependent spectra, the gradual transition from local excited state to intramolecular charge transfer state with the increasing solvent polarity is clearly resolved. The transition time in high polarity solvent DMF is very fast, around 0.5 ps, resulting in a low fluorescence quantum yield. While in aggregate state, the intramolecular torsion is restricted and the local environment becomes less polar. Thus, the intramolecular charge transfer state is eliminated and efficient AIE occurs.
氰基取代的寡聚（α-苯乙炔基）-1,4-双（R-氰基-4-二苯基氨基苯乙烯基）-2,5-二苯基苯（CNDPASDB）分子在溶液和聚集态中通过时间分辨荧光技术进行研究。CNDPASDB 表现出强烈的溶剂极性依赖性聚集诱导发射（AIE）特征。通过时间相关光谱，可以清楚地分辨出随着溶剂极性的增加，从局域激发态到分子内电荷转移态的逐渐转变。在高极性溶剂 DMF 中，跃迁时间非常快，约为 0.5 ps，导致荧光量子产率低。而在聚集态中，分子内扭转受到限制，局部环境变得不那么极性。因此，分子内电荷转移态被消除，并且发生有效的 AIE。
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