Studies on the Excitation of a Surface-Modified Electrode by Surface Plasmon Field

本文研究了表面等离子体电磁场对表面修饰金电极的激发机理。表面等离子体波是由入射光转化为金属表面的电荷密度波。该场在金表面具有很强的局域性，适合于激发金表面的光功能分子。此外，与入射光强相比，场强也有显著提高。与传统的直接光激发相比，这些特征提供了在金表面上激发卟啉自组装单分子膜的相当大的优势。特别是表面等离子体激发，由于分子的聚集作用，可以有效地激发近红外光谱中非常微弱的吸收带，因为场增强作用随着入射光波长的增加而增加。为了实际应用，还研究了增强的表面等离子体场局域化到金表面的波长尺寸的势垒中。

In this study, the excitation mechanism of surface-modified gold electrode by the electromagnetic field of surface plasmon has been studied. Surface plasmon is charge density wave propagating on metal surface converted from the incident light. The field is strongly localized on the surface and suitable for excitation of photofunctional molecules attached on the gold surface. Moreover, the field intensity is remarkably enhanced compared with the incident light. These features have offered considerable advantages over conventional direct photoexcitation upon excitation of porphyrin self-assembly monolayers on a gold surface. Particularly, surface plasmon excitation is effective for the excitation of very slight absorption bands in near-IR due to the molecular aggregation, because the field enhancement increases with increasing wavelength of the incident light. Localization of the enhanced surface plasmon field into the wavelength-sized wells on the gold surface also has been studied for the practical applications.