聚合物O-PPV的链间相互作用的研究

近年来,聚对苯乙炔(PPV)及其衍生物作为一类性能优良的电致发光材料而受到人们的广泛关注1].这是因为聚合物发光材料能通过化学裁剪方法来改善发光效率、颜色、成膜性等特性.载流子形成激子以及激子的辐射和非辐射衰减过程向来是聚合物发光二极管(LEDs)发光的重要环节,因此研究聚合物的光物理过程对提高器件的发光特性是非常重要的.

Interchain Interaction in Poly[(2,5-diphenylene-1,3,4-oxadiazole)-4,4'-vinylene](O-PPV)

The photoluminescence(PL) properties of poly (2, 5 - diphenylene - 1, 3, 4 - oxadiazole) - 4, 4' - viny-lene] (O - PPV) are investigated using absorption and excitation measurements for different concentration ratios of solid-state O - PPV/ PEO (polyethylene oxide ) blends, as well as by comparing PL spectra for dilute solution and solid state pristine O - PPV. The solid film of O - PPV/PEO is prepared to investigate the interaction between polymers. The O - PPV molecules are dispersed into PEO which is used as a inert material in order to change the interaction between O - PPV. In the O -PPV/PEO blends, it is found that the PL spectra excited by 300nm for different concentration ratios are different. There are three peaks in the PL spectra of 1: 100 and 1: 200 (O - PPV/PEO) blends, and the relative intensities of peaks at 500nm and 460nm gradually decrease with lowering the concentrations of O - PPV. There leaves one peak at 416nm when the ratio of O - PPV to PEO is below 1: 300, and PL shape does not change any longer. The results show that the solid-state O - PPV emission arises from interchain charge-transfer states due to interchain effects.According to the absorption and photoluminescence spectra of the solid films, it is also believed that there are types of localized and delocalized states in conjugated polymers. The two types of states have different effects on charge-transfer state in different concentrations of solid films.