可溶性聚对苯乙炔衍生物非线性光学效应研究

Nonlinear Optical Properties of Soluble Poly (phenylene vinylene) Derivatives

以对甲氧基苯酚和溴代烷为原料,经过脱氯化氢反应合成了三种可溶性非对称烷氧基取代聚对苯乙炔 (PPV)衍生物,分别为聚(2 甲氧基 5 丁氧基)对苯乙炔(PMOBOPV)、聚[2 甲氧基 5 (3′ 甲基)丁氧基]对苯乙炔 (PMOMBOPV)和聚(2 甲氧基 5 辛氧基)对苯乙炔(PMOCOPV)。利用后向式简并四波混频(DFWM)研究了它们 的三阶非线性光学性质。结果表明PMOBOPV,PMOMBOPV和PMOCOPV的三阶非线性极化率(χ(3))分别为 3.14×10-10,5.96×10-10和3.71×10-10esu,相应的二阶分子超极化率(γ)分别为4.22×10-28,7.78×10-28和 5.00×10-28esu。分析了分子结构对聚对苯乙炔衍生物非线性光学性质的影响。采用分光光度计对三种材料的 光学禁带宽度(Eg)进行了测量,线性拟合的结果表明PMOBOPV,PMOMBOPV和PMOCOPV的Eg值分别为 2.08,2.03及2.05eV。

The soluble π-conjugated polymer materials, poly(2-methoxy-5-butoxy)-p-phenylene vinylene (PMOBOPV), poly[2-methoxy-5-(3′-methyl)butoxy]-p-phenylene vinylene (PMOMBOPV) and poly(2-methoxy-5-octoxy)-p-phenylene vinylene (PMOCOPV), were prepared by dehydrochlorination reaction from p-methoxylphenol and alkyl bromide as raw materials. Their third-order nonlinear optical properties were studied with the backward degenerate four-wave mixing (DFWM) at 532 nm. The experimental result showed that the third-order nonlinear optical susceptibilities x(3) values of PMOBOPV, PMOMBOPV and PMOCOPV were 3.14 × 10-10, 5.96 × 10-10 and 3.71 × 10-10 esu, respectively, and corresponding hyperpolarizability γ values were 4.22 × 10-28, 7.78 × 10-28 and 5.00 × 10-28 esu, respectively. The effects of molecular structures on nonlinear optical properties of poly(p-phenylene vinylene) (PPV) derivatives were also studied. Moreover, the optical bandgaps, Eg, of PPV derivatives were measured by spectrometer and the result of data fitting showed that Eg values of PMOBOPV, PMOMBOPV and PMOCOPV were 2.08 eV, 2.03 eV and 2.05 eV, respectively.