Photoluminescence study on exciton migration and trapping in a copolymer based on poly(fluorene)
Photoluminescence study on exciton migration and trapping in a copolymer based on poly(fluorene)
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DOI：
10.1039/b000379o
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发表时间：
2000
影响因子：
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通讯作者：
Jeong-Ik Lee;Taehyoung Zyung;Robert D. Miller;Yonghee Kim;S. Jeoung;Dongho. Kim
中科院分区：
文献类型：
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作者：
Jeong-Ik Lee;Taehyoung Zyung;Robert D. Miller;Yonghee Kim;S. Jeoung;Dongho. Kim
研究了聚[9,9-二（2′-乙基己基）芴-2,7-二基]和聚[9,9-二（2′-乙基己基）芴-2,7-二基-co-α-氰二苯基-4,4′-二基]共聚物的稳态和时间分辨光致发光光谱。在THF中，共聚物表现出均聚物特有的蓝色发射带以及含有共聚单体单元的显色片段产生的另一个发射带。共聚物薄膜中均聚物发射带的完全抑制表明激子有效迁移和捕获到含有共聚单元的片段中。与均聚物相比，共聚物薄膜中的激子迁移和捕获引起了光致发光的红移。时间分辨的光致发光结果也与激子从芴聚合物单元向氰二苯乙烯共聚单体单元组成的捕获位点的快速迁移一致。激子捕获过程导致发射光谱中的红移，从而增强了共聚物相对于均聚物的颜色稳定性。
Steady-state and time-resolved photoluminescence spectra of poly[9,9-bis(2′-ethylhexyl)fluorene-2,7-diyl] and a copolymer of poly[9,9-bis(2′-ethylhexyl)fluorene-2,7-diyl-co-α-cyanostilbene-4,4′-diyl] were investigated. In THF, the copolymer exhibits the characteristic blue emission band of the homopolymer together with another emission band arising from chromophoric segments containing comonomer units. A total suppression of the homopolymer emission band in copolymer thin film demonstrates the efficient exciton migration and trapping into the segments containing comonomer units. Exciton migration and trapping in copolymer thin film gives rise to a red-shift in photoluminescence as compared with the homopolymer. Time-resolved photoluminescence results are also consistent with the facile exciton migration from fluorene polymer units to trapping sites composed of cyanostilbene comonomer units. The exciton trapping processes result in a red-shift in the emission spectrum with enhanced color stability in the copolymer relative to the homopolymer.