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

利用金属表面的表面等离子体激元(SPP)研究了金属表面有机超薄膜的结构和功能。利用SPP激发产生的薄膜散射光对金属膜和金属表面的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表面光滑。利用衰减全反射(ATR)配置的反向入射光观察到了新的光发射。认为表面等离子体激发子是由薄膜表面粗糙度和/或薄膜结构不均匀引起的，部分表面等离子体激发子被转换为棱镜面的光发射。由于SPP的激发，液晶分子在细胞中的排列可以用ATR测量来评估。通过对理论ATR曲线和实验ATR曲线的拟合，确定了薄单元和厚单元的倾角分布。建立了一个探测瞬逝磁场的系统。测量了覆盖有硫化镉的针尖发出的发光为瞬逝光场。在ATR构型中，观察到了由SPP激发产生的逝去场与激光入射角度的函数关系。还测量了光异构体超薄膜的ATR特性。螺吡喃和偶氮染料LB膜中的光异构化改变了ATR的性质。研究了利用SPP激发增强花菁LB膜光电器件的短路光电流。在ATR构型中，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.