Photochemical Hole Burning of Organic Dye Doped in Inorganic Semiconductor: Zinc Porphyrin in Titanium Dioxide

One of the topics of photochemical hole burning (PHB) materials is high-temperature PHB. This is not only important for optical applications but also important for purely scientific studies because high-temperature materials expand the temperature range in which we can obtain informations about electron-phonon interactions, structural relaxations, and photoinduced processes of guest-host systems. Although some of inorganic PHB materials show an excellent property that a hole can be burnt even at room temperature, holes of only few organic chromophores are observed above 80 K [1]. PHB systems with inorganic matrices have a possibility of showing high-temperature PHB for organic dyes. Organic dyes adsorbed on the surface of γ-almina are reported to show high-temperature hole formation and small temperature dependence of Debye-Waller factor (DWF) [2].