Enhancement of photochromic molecule decolorization by coating a thin Ti(O) layer over gold nanoparticles.

Photochemical decolorization reaction of terarylenes with a hydroxy or a methoxy group is studied on the surface of gold nanoparticles (AuNPs)/TiO₂ thin hybrid film. AuNPs were deposited on TiO₂ film after UV irradiation with HAuCl₄. The colored form of terarylenes could not be decolorized at the bare AuNPs on TiO₂ under irradiation of green light (530 nm in wavelength). On the other hand, effective decolorization activity of terarylene, having a hydroxy group, was observed at the surface of AuNPs/TiO₂ hybrid film with an optimized number of Ti(O) insulator layers on AuNPs. The mechanism for the enhanced decoloration is proposed based on the difference in the substituent of the terarylenes. [ABSTRACT FROM AUTHOR]