金属ナノ粒子を用いた積層型光電変換素子の開発

抄録

Hybrid nanoassemblies with metal nanoparticle monolayer and polymer nanosheets containing ruthenium (II) tris(2,2’-bipyridine) derivative (Ru(bpy)₃²⁺) were fabricated by the Langmuir-Blodgett technique and immersion method. Metal nanoparticles, gold and silver nanoparticles, were immobilized onto polymer Langmuir-Blodgett films containing amino end group (p(DDA/DADOO)) through immersion into a metal nanoparticle aqueous solution. This allows monolayer formation of metal nanoparticles which were uniformly distributed on polymer LB films. Emission intensity from the ruthenium complex was enhanced approximately four-fold in the presence of silver nanoparticles. Besides effective photocurrent generation was achieved by p(DDA/Ru)-Ag hybrid assembly system. Localized surface plasmon of the silver nanoparticle effectively excites ruthenium complex, while the excited ruthenium complexes were quenched by gold nanoparticles. This is due to the spectroscopic properties of metal nanoparticles immobilized on the polymer LB films; strong absorption band of silver nanoparticle arrays were overlapped with absorption band of ruthenium complex, and that of gold nanoparticle arrays were superimposed on the emission band of ruthenium complex. These findings suggest that spectroscopic optimization for the combination of photo- and electro-functional molecules and metal nanoparticles are of important in order to utilize localized surface plasmon electromagnetic field more efficiently.