Bruevich V V, Makhmutov T Sh, Elizarov S G, Nechvolodova E M, Paraschuk D Yu
Faculty of Physics and International Laser Center, Lomonosov Moscow State University, Moscow 119992, Russia.
J Chem Phys. 2007 Sep 14;127(10):104905. doi: 10.1063/1.2767266.
Intermolecular donor-acceptor charge transfer complex (CTC) formed in the electronic ground state between poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) and 2,4,7-trinitrofluorenone (TNF) has been investigated by Raman and optical absorption spectroscopies. Blending of MEH-PPV and TNF results in appearance of the CTC absorption band in the optical gap of the both components and in changes in the characteristic MEH-PPV Raman bands including shifts, change in bandwidth, and intensity. The experimental data are similar in films and solutions indicating the CTC formation in both. We associate the low-frequency shift of the strongest MEH-PPV Raman band at approximately 1580 cm(-1) reaching 5 cm(-1) with partial electron transfer from MEH-PPV to TNF amounting approximately 0.2e(-). We suggest that polymer conjugated segments can form the CTC of variable composition MEH-PPV:TNF=1:X, where X<or=0.5 is per MEH-PPV monomer unit. Our Raman data indicate that MEH-PPV conjugated segments involved in the CTC become more planar; however, their conjugation length seemingly does not change.
通过拉曼光谱和光吸收光谱研究了聚2-甲氧基-5-(2-乙基己氧基)-1,4-亚苯基乙烯撑与2,4,7-三硝基芴酮(TNF)在电子基态下形成的分子间供体-受体电荷转移复合物(CTC)。MEH-PPV与TNF的混合导致在两种组分的光学带隙中出现CTC吸收带，并使MEH-PPV特征拉曼带发生变化，包括位移、带宽变化和强度变化。薄膜和溶液中的实验数据相似，表明两者中均形成了CTC。我们将MEH-PPV最强拉曼带在约1580 cm⁻¹处的低频位移达5 cm⁻¹与从MEH-PPV到TNF的约0.2e⁻的部分电子转移联系起来。我们认为聚合物共轭链段可以形成组成可变的MEH-PPV:TNF = 1:X的CTC，其中每个MEH-PPV单体单元的X≤0.5。我们的拉曼数据表明，参与CTC的MEH-PPV共轭链段变得更加平面化；然而，它们的共轭长度似乎没有变化。
