No abstract

No abstract

Meso-macroporous anatase TiO2 films, described in a previous work, have been used for the first time as electrodes for dye-sensitized photoelectrochemical cells. The mesopores provide a large surface area that is favorable for efficient light absorption, and the macropores serve as pathways for diffusion of electroactive agents (EAAs). Although the introduction of macropores led to an improvement in the magnitude of the short-circuit photocurrent (Jsc), electron recombination on the SnO2 substrate surface at the bottom of the macropores deteriorated the open-circuit voltage (Voc). This unfavorable process has been depressed by applying a thin (200 to 300 nm) TiO2 film between the meso-macroporous film and the SnO2 substrate, to obtain finally a dye-sensitized photoelectrode with a Voc nearly identical with, and a Jsc superior to, the values for a conventional porous TiO2 film electrode.

We investigate the spectrally narrowed emission ͑SNE͒ from rhodamine 6G infiltrated in synthetic opals enhanced by the surface-plasmon resonance effect of Ag particles anchored on the internal surface of the synthetic opals. At a larger number density of Ag particles, SNE is observed at a lower pump intensity, and the intensity is reduced to one-tenth without Ag. The enhancement factor is qualitatively reproduced by theoretical calculations as a function of the amount of Ag particles. These results indicate that the enhancement is caused by the surface-plasmon resonance.

We report on the observation of spectrally narrowed emission (SNE) from rhodamine 6G infiltrated in synthetic opals, and the enhancement of the spectral narrowing by the surface plasmon resonance effect of Ag particles anchored on the internal surface of the opals. With Ag particles, SNE is observed at a lower pump intensity, and the threshold of the spectral narrowing is one-tenth lower than that without Ag. It was clarified that enhancement is not caused by the light scattering of the Ag particles, but by the surface plasmon resonance.