Extremely sensitive detection of transient species in laser flash photolysis of ultrathin organized molecular films by optical waveguide
Extremely sensitive detection of transient species in laser flash photolysis of ultrathin organized molecular films by optical waveguide
复制标题
通过光波导对超薄组织分子膜的激光闪光光解中的瞬态物质进行极其灵敏的检测
DOI：
10.1117/12.221485
复制
发表时间：
1995
期刊：
影响因子：
--
通讯作者：
H. Sakaguchi
中科院分区：
文献类型：
--
作者：
T. Nagamura;Daizo Kuroyanagi;Kyoichi Sasaki;H. Sakaguchi
通过光波导 (OWG) 方法灵敏地检测超薄聚合物和 Langmuir-Blodgett (LB) 薄膜的脉冲激光激发下的瞬态物质。在OWGs表面制备了聚甲基丙烯酸甲酯薄膜中的四甲苯基卟啉和与双十八烷基二甲基铵混合的LB薄膜中的两亲性四苯基卟啉。这些薄膜在受控环境下用 ns Nd:YAG 激光器的二次谐波激发。通过 Ar+ 激光、He-Ne 激光或二极管激光作为探针，可以灵敏地检测激发的三重态卟啉的瞬态吸收。通过本方法观察到仅具有两个单层的LB膜的瞬时吸收。与传统的正入射测量相比，灵敏度提高了约一百倍。在聚合物膜和LB膜中观察到激发三重态卟啉的不同衰变动力学，这归因于发色团的不同空间分布。
Transient species upon pulsed laser excitation of ultrathin polymer and Langmuir-Blodgett (LB) films was detected sensitively by the optical waveguide (OWG) method. Tetratolylporphyrin in poly(methylmethacrylate) films and amphiphilic tetraphenylporphyrin in mixed LB films with dioctadecyldimethylammonium were prepared on the surface of OWGs. These films were excited with the second harmonics of a ns Nd:YAG laser in controlled environment. The transient absorption of excited triplet porphyrins was detected sensitively by Ar+ laser, He-Ne laser, or diode lasers as a probe. Transient absorption in LB films with only two monolayers was observed by the present method. It was about hundred times increase of sensitivity as compared with a conventional normal incidence measurement. Different decay dynamics were observed for excited triplet state porphyrins in polymer films and in LB films, which was attributed to the different spatial distribution of chromophores.