Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA.
J Phys Chem B. 2013 Apr 25;117(16):4204-15. doi: 10.1021/jp302772y. Epub 2012 Aug 17.
A series of novel oligothiophene-perylene bisimide hybrid (DOTPBI) dendrimers up to the second generation (G0, G1, and G2) were investigated. Optical measurements such as nonlinear optical and time-resolved spectroscopy, including two-photon absorption, fluorescence upconversion, and excited state transient absorption were carried out. Results of these measurements revealed the ability of these molecules to undergo intramolecular fluorescence resonance energy transfer (FRET) from the dendritic oligothiophenes (DOT) to the perylene bismide (PBI) moiety. The delocalization length and the photoinduced electron transfer (PET) rate were investigated as a function of dendrimer generation. A fast energy transfer process from the DOT dendron to the PBI core was observed. For the case of the G2 dendrimer, with relatively large thiophene dendrons attached to the bay area of the perylene bisimide, the PBI core is highly twisted and its ability to self-assemble into π-π stacked aggregates is destroyed. As a result, among the three generations studied, G1, which has the best two-photon cross section and the most efficient energy transfer, is the best light harvesting material.
研究了一系列新型的寡噻吩-对苯二甲酰亚胺混合（DOTPBI）树枝状大分子，最高可达第二代（G0、G1 和 G2）。进行了光学测量，如非线性光学和时间分辨光谱，包括双光子吸收、荧光上转换和激发态瞬态吸收。这些测量结果表明，这些分子能够从树枝状寡噻吩（DOT）到对苯二甲酰亚胺（PBI）部分进行分子内荧光共振能量转移（FRET）。作为树枝状大分子代的函数，研究了离域长度和光致电子转移（PET）速率。观察到从 DOT 树枝到 PBI 核心的快速能量转移过程。对于 G2 树枝状大分子，由于较大的噻吩树枝连接到对苯二甲酰亚胺的海湾区域，PBI 核心高度扭曲，其自组装成π-π堆积聚集体的能力被破坏。结果，在所研究的三代中，G1 具有最佳的双光子截面和最高效的能量转移，是最佳的光收集材料。
