New Kind of Hyperbranched Conjugated Polymers Containing Alkyl-Modified 2,4,6-Tris(thiophen-2-yl)-1,3,5-triazine Unit for Enhancing Two-Photon Absorption

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• 作者：Pengcheng Zhou ; Cheng Zhong ; Xingguo Chen ; Jingui Qin ; In锚s Mariz ; Ermelinda Ma莽么as
• 刊名：Macromolecules
• 出版年：2014
• 出版时间：October 14, 2014
• 年：2014
• 卷：47
• 期：19
• 页码：6679-6686
• 全文大小：481K
• ISSN：1520-5835

文摘

Two series of hyperbranched polymers based on alkyl-modified 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine central units linked through fluorene bridges of different lengths have been synthesized via Suzuki coupling. The two series of polymers differ in the position of alkyl substitution within the thienyl group, which can be either closer to the triazine core (P0鈥?b>P10) or to the fluorene bridge (P0鈥测€?b>P10鈥?. Introduction of a hexyl group at one of the 尾-positions of the thienyl group improves the solubility of the polymers. A good control over the ratio of triazine and fluorene units allows for the systematic study of the polymer composition effects on the electrochemical, linear, and nonlinear photophysical properties. The nonlinear absorption has been shown to have a noticeable promotion with increasing molar ratio of the triazine core, while the emission quantum yield decreases. The position of alkyl substitution within the thienyl group has a significant effect on the two-photon absorption cross section. Substitution at the 尾-position of the thienyl group closer to the triazine unit favors nonlinear absorption in the P0鈥?b>P10 series when compared to the P0鈥测€?b>P10鈥?series. These polymers perform considerably better as nonlinear absorbers than their unsubstituted analogues.