带有咔唑支链的聚乙炔的发光特性研究

在室温下,对单取代聚乙炔(PACz-1)和两种双取代聚乙炔PACz-2(m=3)、PACz-2(m=9)]的荧光特性和电子结构进行了研究.每种聚乙炔的支链上有一个咔唑单元.虽然它们的分子结构不同,但它们的稀溶液却有相同的吸收峰和强的绿色荧光发射峰,并且它们的吸收谱和发射谱很相似.当溶液的浓度增大到～1×10~(-3)M时,发现有强的绿色荧光发射,峰位位于475 nm.运用Huckel扩展紧束缚计算方法,从理论上计算了带咔唑支链的聚乙炔的电子结构。结果表明单取代聚乙炔和两种双取代聚乙炔的吸收峰、低浓度下的360 nm紫外光发射峰与高浓度下的475 nm的绿色荧光峰都是由于聚乙炔支链上咔唑生色团引起的.

Origin of the blue emissions of polyacetylenes bearing carbazole side groups

The optical properties and electronic structures of one mono-substituted polyacetylene and two di-substituted polyacetylenes have been investigated. Each of the substituted polyacetylenes bears a carbazole unit in the side chain. In spite of the differences in their molecular structures,the dilute solutions(～1 × 10－6 M)of these substituted polyacetylenes exhibit the same absorptions and the same deep-blue emissions(～360 nm). Interestingly,the absorption and emission spectra of these substituted polyacetylenes are similar to those of the small molecule carbazole. As the concentration of the substituted polyacetylenes increases to about 1 × 10－3 M,we have detected intense blue emissions at about 475 nm. Using Huckel tight binding programs,we have calculated the electronic structures of the carbazole-containing polyacetylenes. Our results indicate that the absorption,the deep-blue emission(～360 nm)and the intense blue emission(～475 nm)originate from the carbazole chromophores in the side chain.