Evaluation of structure and functions of organic ultrathin films on metal films utilizing surface plasmon polariton excitation

利用金属表面激发的表面等离子激元（SPP），研究了金属薄膜上有机超薄膜的结构和功能。利用SPP激发产生的散射光，对金属表面的金属膜和LB膜的表面粗糙度进行了评价。LB膜在蒸发银膜上的散射光比溅射膜上的散射光强。结果表明，溅射膜的表面比蒸发膜光滑。在衰减全反射（ATR）结构中，通过反向入射光观察到新的光发射。认为薄膜的表面粗糙度和/或薄膜的非均匀结构激发了SPPs，并将部分SPPs转化为棱镜侧的光发射。由于SPP激发，液晶分子在细胞中的排列可以用ATR测量来评估。通过理论ATR曲线与实验ATR曲线的拟合，确定了薄壁和厚壁的倾斜角度分布。构建了一个检测倏逝场的系统。从覆盖有cd的针尖发出的发光被测量为倏逝场。在ATR结构中观察到由SPP激发引起的倏逝场是激光束入射角的函数。对光异构体超薄膜的ATR性能也进行了测定。由于螺吡烷和偶氮染料LB膜的光异构化，ATR性能发生了变化。研究了利用SPP激励增强merocyanine LB薄膜光电器件的短路光电流。在ATR结构中，在入射光的SPP激发角附近观察到较大的光电流。

Structure and functions of organic ultrathin films on metal films have been investigated utilizing surface plasmon polaritons (SPP) excited on the metal surface. Surface roughnesses of metal films and LB films on the metals were evaluated using scattered light from thin films caused by SPP excitation. Scattered light from LB films on evaporated silver films was stronger than that on the sputtered films. The results showed that sputtered films had smoother surface than evaporated films. New light emission was observed by the reverse incident light in the attenuated total reflection (ATR) configuration. It Was thought that SPPs were excited by surface roughness of thin films and/or non-uniform structure of the films and some SPPs were converted to the light emission from the prism side. Alignments of liquid crystal molecules in cells could be evaluated using ATR measurements due to SPP excitations. Profiles of the tilt angles were decided in the thin and thick cells by fitting theoretical ATR curves to the experimental ones. A system was constructed to detect evanescent fields. Luminescent light from a needle tip covered with CdS was measured to be evanescent fields. Evanescent fields due to SPP excitations were observed as a function of the incident angle of the laser beam in the ATR configuration. ATR properties were also measured for photoisomeric ultrathin films. The ATR properties changed due to the photoisomerization in spiropyrane and azo dye LB films. Enhancement of short-circuit photocurrents utilizing SPP excitations was investigated for merocyanine LB film photoelectric device. Large photocurrents were observed around the SPP excitation angles of the incident light in the ATR configuration.