枝状聚硅烷光学及其稳定性

Optical Properties and Stability of Branched Polysilanes

利用W urtz法合成了线形聚(甲基苯基)硅烷和枝状聚(苯基-二甲基)硅烷、聚(苯基-甲基苯基)硅烷。通过紫外吸收和荧光光谱测试技术测定了光学性能,用热重分析测定了热性能。结果表明,枝状聚硅烷的吸收带拖尾至可见光区,对应的荧光发射也较线形聚硅烷有较大的红移,说明其能带隙较低,且枝状聚硅烷有较好的热稳定性。重点研究了聚硅烷的热降解动力学和光稳定性,结果表明,枝状聚硅烷的热分解活化能比线性聚硅烷的高32.4 kJ/mol。将其溶于甲苯,用254 nm的紫外光照射,结果显示,线性聚硅烷的吸收强度随照射时间的增加逐渐降低,而枝状聚硅烷的吸收强度几乎不变,说明枝状聚硅烷具有较好的光热稳定性。

One linear polysilane, poly （methylphenyl）silane, and two branched polysilanes poly （phenyl- dimethyl） silane and poly （phenyl-methylphenyl）silane, were synthesized via Wurtz reductive coupling reaction. Their Ultraviolet absorption（UV） and Photoluminescence（PL） spectra were obtained to characterize their optical properties, and thermogravity analysis（TGA） was used to characterize their thermal stability. The absorption bands of the branched polysilanes tailed to visible region and the corresponding emission peaks showed obvious red shift compared with that of the linear one, indicating that the branched polysilanes had lower energy band gap than the linear one. In addition, the branched polysilanes exhibited better thermal stability. Under the irradiation of ultraviolet light of 245 nm, the absorption intensity of the linear polysilane gradually fell with irradiation time, while that of the branched polysilanes remained almost unchanged, indicating that the branched polysilanes had better ultraviolet stability than the linear one. Keywords