Low-Bandgap Conjugated Donor−Acceptor Copolymers Based on Porphyrin with Strong Two-Photon Absorption

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• 作者：Xuebin Huang ; Qinqin Shi ; Wei-Qiang Chen ; Chunli Zhu ; Weiyi Zhou ; Zhen Zhao ; Xuan-Ming Duan ; Xiaowei Zhan
• 刊名：Macromolecules
• 出版年：2010
• 出版时间：December 14, 2010
• 年：2010
• 卷：43
• 期：23
• 页码：9620-9626
• 全文大小：871K
• 年卷期：v.43,no.23(December 14, 2010)
• ISSN：1520-5835

文摘

Two new low-bandgap, conjugated donor (D)−acceptor (A) copolymers of porphyrin with 2,3-bis(4-trifluoromethylphenyl)pyrido[3,4-b]pyrazine (P1) and perylene diimide (P2) were synthesized by Sonogashira coupling polymerization and compared with porphyrin−dithienothiophene D−D copolymer (P3). All these polymers possess good thermal stability with decomposition temperatures over 300 °C. Polymers P1 and P2 in films exhibit strong absorption in near-IR (820−950 nm) with optical bandgaps as low as 1.15 eV; their Q-bands red shift 60−190 nm compared to that of P3, while the Soret bands are similar. The HOMO (−5.3 to −5.4 eV) and LUMO (−3.6 to −4.0 eV) of the D−A polymers are lower than that of the D−D polymer. Two-photon absorption (2PA) properties of the polymers were investigated by the femtosecond Z-scan method. The D−A polymer P2 exhibits 2PA cross sections over 7000 GM/repeat unit at telecommunication wavelengths (1320 and 1520 nm), larger than that of P1 and P3, due to the very strong, rigid, and coplanar perylene diimide acceptor and strong D−A intramolecular charge transfer.