Time-Resolved Fluorescence Study of Aggregation-Induced Emission Enhancement by Restriction of Intramolecular Charge Transfer State
Time-Resolved Fluorescence Study of Aggregation-Induced Emission Enhancement by Restriction of Intramolecular Charge Transfer State
复制标题
通过限制分子内电荷转移状态来增强聚集诱导发射的时间分辨荧光研究
DOI：
10.1021/jp909063d
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发表时间：
2010-01-14
影响因子：
3.3
通讯作者：
Sun, Hong-Bo
中科院分区：
文献类型：
--
作者：
Gao, Bing-Rong;Wang, Hai-Yu;Sun, Hong-Bo
用时间分辨荧光技术研究了氰基取代的低聚（α-亚苯基亚乙烯基）-1，4-双（R-氰基-4-二苯胺基苯乙烯基）-2，5-二苯基苯（CNDPASDB）分子在溶液和聚集态下的荧光性质。CNDPASDB具有很强的溶剂极性依赖性的聚集诱导发光（AIE）特性。通过含时光谱，可以清楚地分辨出随着溶剂极性的增加，从局部激发态到分子内电荷转移态的逐渐转变。在高极性溶剂DMF中的跃迁时间非常快，约为0.5 ps，导致低荧光量子产率。在聚集态时，分子内的扭转受到限制，局部环境的极性减弱。因此，分子内电荷转移态被消除，并且有效的AIE消除。
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.