Approaches to Improvement of Stabilities and Efficiencies of Photoenergy Conversion Devices Based on Plasmon Induced Charge Separation

摘要

It is known that metal nanoparticles exhibit localized surface plasmon resonance (LSPR) with the resonant light irradiation. When the resonant light irradiates to a plasmonic metal nanoparticle, light energy can be localized in nanospaces around the surface of the nanoparticle. Hence, LSPR is expected to be an innovative technology in order to utilize photoenergy with high efficiency. Furthermore, a plasmonic metal nanoparticle combined with a semiconductor exhibit plasmon induced charge separation (PICS). When the resonant light irradiates to a plasmonic metal nanoparticle on an n-type semiconductor, electrons in the metal nanoparticle transfer to the semiconductor. As a result, oxidative and reductive reactions occur on the surfaces of the metal nanoparticle and the semiconductor, respectively. Therefore, PICS can be applied to various photoenergy conversion devices, such as photocatalysts and phorovoltaic cells. However, conventional PICS system has some problems to be solved. For example, the oxidation power generated at the metal nanoparticles promotes oxidative dissolution of the metal nanoparticles. Furthermore, the detail mechanism of PICS has been still unclear. In addition, the efficiencies of charge separation have not achieved high enough.