聚苯撑乙烯衍生物链间聚集与链内自聚集对光致发光的影响

Influence of Interchain and Self Intrachain Aggregations on Photoluminescence of a Poly-Phenylenevinylene Derivative

利用Gilch路线合成了具有高度物理缠结的聚苯撑乙烯衍生物(聚2,5-二-辛氧基苯撑乙烯(DOO-PPV)凝胶及短链DOO-PPV粉末,并利用傅里叶变换-红外光谱(FT-IR)及傅里叶变换-拉曼光谱(FT-Raman)进行了结构表征,结果表明,凝胶与其短链DOO-PPV粉末具有相同的化学结构,分子间不存在化学交联.比较了短链DOO-PPV粉末、凝胶、旋涂薄膜的紫外-可见(UV-Vis)光谱、光致发光(PL)光谱及X射线衍射(XRD)图谱,发现在薄膜、短链DOO-PPV粉末及凝胶的PL光谱中,短波长发射峰强度与长波长发射峰强度的比值依次降低,分别为3.24、1.10和0.47.XRD分析表明,凝胶中存在较多有序结构,短链DOO-PPV粉末中分子有序结构较少,薄膜中分子有序性最低;表明固态下DOO-PPV短波长的发射峰与链内自聚集相关,而长波长发射峰与链间聚集有关.

A poly-phenylenevinylene derivative （poly （2,5-dioctyloxy）-p-phenylene vinylene） （DOO-PPV） with a high degree of physical crosslinking （designated the gelation of DOO-PPV） was synthesized and characterized. Analyses of the Fourier transform-infrared （FT-IR） and the Fourier transform-Raman （FT-Raman） spectra indicate that the chemical structure of the gelation of DOO-PPV is accordant with short chain linear molecule of DOO-PPV. Photoluminescence spectra of a thin film, short chain linear molecule, and solid gelation show that the ratio of the intensity at the short wavelength emitting band and at the long wavelength emitting band decreases gradually, the ratio is 3.24, 1.10 and 0.47, respectively. Analysis of X-ray diffraction （XRD） indicated that the existence of a more oriented structure in the gelation of DOO-PPV compared with the short chain molecule and the thin film. This result suggests that interchain and self intrachain aggregations play an important role in the photoluminescence.