N^+离子注入聚对苯乙炔衍生物的非线性光学性能  

Nonlinear Optical Properties of Poly(p-phenylene vinylene) Derivative Modified by N+ Ion Implantation

作　　者：李宝铭[1] 吴洪才[1] 高潮[1] 孙建平[1] 

机构地区：[1]西安交通大学电信工程学院光电技术与太阳能研究所,西安710049

出　　处：《高等学校化学学报》2005年第8期1565-1569,共5页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:60277002);西安交通大学科研基金资助.

摘　　要：以对甲氧基苯酚和溴代异戊烷为原料,用脱氯化氢反应制备可溶性聚[2-甲氧基-5-(3′-甲基)丁氧基]对苯乙炔(MMB-PPV),通过核磁氢谱(1HNMR)和红外光谱(FTIR)对产物分子的结构进行表征.用能量为15keV、剂量为3.8×1015～9.6×1016ions/cm2的氮正离子(N+)对MMB-PPV薄膜进行注入改性.紫外-可见吸收光谱(UV-Vis)显示,注入离子在MMB-PPV薄膜内部引入杂质能级,破坏了分子的共轭结构.随着注入剂量增加,吸收边逐渐向长波方向移动,且分子激发态和基态间的光学带隙由2.12eV减小至1.81eV.用简并四波混频(DFWM)技术研究了离子注入MMB-PPV薄膜的三阶非线性光学性能.结果表明,未注入薄膜的三阶非线性极化率(χ(3))值为7.1×10-10esu,随着注入剂量的增加,χ(3)值逐渐增大,当注入剂量达到3.8×1016ions/cm2时,χ(3)值提高到9.3×10-9esu,继续增加注入剂量,χ(3)值开始下降,当注入剂量为9.6×1016ions/cm2时,χ(3)值降低到1.5×10-10esu.对离子注入MMB-PPV薄膜χ(3)值变化的机理进行了探讨.A soluble poly[-2-methoxy-5-（3′-methyl）butoxy]-p-phenylene vinylene（MMB-PPV） was synthesized by dehydrochlorination reaction from p-methoxylphenol and isoamyl bromide as the raw materials and characterized by 1H NMR and FTIR. The MMB-PPV films were prepared and implanted by nitrogen ion（N^＋） with the dose ranging from 3.8 × 10^15 to 9. 6 × 10^16 ions/cm^2 at an energy of 15 keV. UV-Vis spectra exhibited that the optical absorption in visible region was improved by ion implantation followed by a red shift of optical absorption threshold and the optical bandgap （Eg） between excited state and ground state was reduced from 2.12 eV to 1.81 eV with the increase of ion dose. The third-order nonlinear optical susceptibilities （χ^（3）） were measured by degenerate four-wave mixing（DFWM） technique at 532 nm. Using the relative measurement method, the χ^（3） value of pristine MMB-PPV film was 7. 1 × 10^-1 esu and became larger with the ion dose increasing and reached the maximum value of 9. 3 × 10^-9 esu at an ion dose of 3.8 × 10^16 ions/cm^2 which was almost one order of magnitude higher than that of the pristine MMB-PPV film. With the continuous increase of ion dose the χ^（3） value decreased gradually, and when the ion dose was 9.6 × 10^16 ions/cm^2, the χ^（3） value was minimized to be 1.5 × 10^-1 esu. Moreover, the mechanism responsible for the enhancement of χ^（3） value was also discussed tentatively.

关 键 词：非线性光学 离子注入 聚[2-甲氧基-5-(3′-甲基)丁氧基]对苯乙炔 简并四波混频 

分 类 号：O631[理学—高分子化学]