A new class of second-order non-linear optical material: stilbazolium benzimidazolate derived from alkylsulfonyl substituted stilbazole
作者:Nobukatsu Nemoto、Jiro Abe、Fusae Miyata、Yasuo Shirai、Yu Nagase
DOI:10.1039/a708620b
日期:——
A novel stilbazolium benzimidazolate derivative,i.e. 2-(4-2-[4-(octylsulfonyl)phenyl]ethenyl}pyridinio)benzimidazolate 4a, was prepared by the quaternization reaction of 4-2-[4-(octylsulfonyl)phenyl]ethenyl}pyridine with 2-chlorobenzimidazole, followed by deprotonation with aqueous ammonia. Poly(methyl methacrylate) (PMMA) thin films containing 10 or 20 mass% of 4a were obtained by spin-coating from their THF solutions on an ordinary cover glass substrate. Second-harmonic generation (SHG) measurements of the obtained thin films were carried out by the Maker fringe method using a Q-switched Nd:YAG laser (1064 nm) as an exciting beam after corona-poling. A poled PMMA film containing 10 or 20 mass% of 4a exhibited a second-order non-linear optical (NLO) coefficient, d33 , of 7.6 or 11 pm V–1 , respectively, which was much larger than the d33 value of a PMMA thin film containing 10 mass% of 2-[4-(2-phenylethenyl)pyridinio]benzimidazolate 4c (d33 1.6 pm V–1) or 2-4-[2-(4-octyloxyphenyl)ethenyl]pyridinio}benzimidazolate 4d (d33 0.51 pm V–1). There were no significant differences in linear absorption properties of PMMA films containing 4a, 4c or 4d. The introduction of an octylsulfonyl group at the 4′-position of the stilbazole moiety increases the second-order NLO coefficient.
一种新型的斯堪诺铵苯并咪唑衍生物,即2-(4-2-[4-(辛基磺酰基)苯基]乙烯}吡啶)苯并咪唑盐4a,通过4-2-[4-(辛基磺酰基)苯基]乙烯}吡啶与2-氯苯并咪唑的季铵化反应制备而成,随后用氨水去质子化。将含有10%或20%质量分数的4a的聚(methyl methacrylate)(PMMA)薄膜通过旋涂法从其四氢呋喃溶液中获得,涂在普通的盖玻片基板上。获得薄膜的二次谐波生成(SHG)测量采用Maker fringe方法,使用Q开关Nd:YAG激光器(1064 nm)作为激发光束,经过电晕极化处理。含有10%或20%质量分数的4a的极化PMMA薄膜展示了二阶非线性光学(NLO)系数d33分别为7.6或11 pm V–1,显著高于含有10%质量分数的2-[4-(2-苯乙烯基)吡啶]苯并咪唑盐4c(d33为1.6 pm V–1)或2-4-[2-(4-辛氧基苯基)乙烯]吡啶}苯并咪唑盐4d(d33为0.51 pm V–1)。含有4a、4c或4d的PMMA薄膜在线性吸收特性上没有显著差异。将辛基磺酰基引入斯堪诺基团的4′位,提高了二阶NLO系数。