Beijing National Laboratory for Molecular Sciences, The Key Laboratory of Bioorganic Chemistry and Molecular Engineering of the Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
Chem Asian J. 2010 Jan 4;5(1):105-13. doi: 10.1002/asia.200900245.
A series of gradient pi-conjugated dendrimers and their corresponding models based on 5,5,10,10,15,15-hexahexyltruxene moieties as nodes and oligo(thienylene vinylene) (OTVs) units with different lengths as branching arms are synthesized in good yields through Wittig-Horner reactions. All new compounds are fully characterized by (1)H and (13)C NMR spectroscopy, elemental analysis, and MALDI-TOF MS or ESI-MS. Investigation of their photophysical properties reveals that the gradient dendritic scaffold not only results in a higher molar absorption coefficient and broader absorption region than those of their corresponding model compounds, but also improves the PL quantum yields relative to the corresponding OTVs. The suitable HOMO and LUMO levels as well as excellent film forming properties make these molecules potential candidates for organic solar cells. Solution-processed bulk heterojunction solar cells using these dendrimers as donor and [6,6]-phenyl-C(61) butyric acid methyl ester as acceptor are prepared and tested. The power conversion efficiency of the devices based on G0-4-2 is 0.40 % under illumination of air mass 1.5 and 100 mW cm(-2). This is the highest record value for OTV-based materials to date. Although the absorption band of dendrimer G0-4-2 is much narrower than that of poly(3-hexylthienylene vinylene) (P3HTV), the efficiency of its solar cell device is almost twice that of the device based on P3HTV. This result shows clearly the advantage of gradient dendritic structures as active materials for photovoltaic cells.
一系列基于 5,5,10,10,15,15-六己基三噻吩作为节点和不同长度的齐聚噻吩乙烯（OTVs）作为支化臂的梯度 -π 共轭树枝状大分子及其相应模型通过 Wittig-Horner 反应以高产率合成。所有新化合物均通过（1）H 和（13）C NMR 光谱、元素分析、MALDI-TOF MS 或 ESI-MS 进行了充分的表征。对其光物理性质的研究表明，梯度树枝状支架不仅导致摩尔吸光系数和吸收区域比相应的模型化合物更高，而且相对于相应的 OTVs 提高了 PL 量子产率。合适的 HOMO 和 LUMO 能级以及优异的成膜性能使这些分子成为有机太阳能电池的潜在候选者。使用这些树枝状大分子作为供体和[6,6]-苯基-C（61）丁酸甲酯作为受体的溶液处理体异质结太阳能电池进行了制备和测试。基于 G0-4-2 的器件在空气质量 1.5 和 100 mW cm(-2)的光照下的功率转换效率为 0.40%。这是迄今为止基于 OTV 材料的最高记录值。尽管树枝状大分子 G0-4-2 的吸收带比聚（3-己基噻吩乙烯基）（P3HTV）窄，但它的太阳能电池器件的效率几乎是基于 P3HTV 的器件的两倍。这一结果清楚地表明了梯度树枝状结构作为光伏电池活性材料的优势。
