Fabrication of composite structure of honeycomb film and luminescent nanoparticles containing lanthanide complexes

Micropatterned films are attractive materials with potentials applicable in the fields of photonics, electronics, biotechnology, and so on. Fabrication of honeycomb-patterned microporous films ("honeycomb films") by casting dilute solution of various types of polymers under high humidity has been already reported. Introduction of luminescent nanoparticles into micropores of the film is investigated to realize photofunctional materials. Novel luminescent monodisperse nanoparticles containing europium or terbium complexes have been prepared for this experiment. By a scanning electron microscope (SEM), many wrinkles were observed on the surface of lanthanide-containing nanoparticles. Zeta potential of the lanthanide-containing nanoparticles was positive. Composites of honeycomb film and the nanoparticles, the latter embedded in the micropores, were fabricated by dropping water dispersion of mixture of the europium-, terbium-, and no-dye-containing nanoparticles on the films. The number of the nanoparticles in a micropore was estimated no less than 400 by analyzing SEM images. The ratio of emission intensity of terbium to that of europium in the individual micropores of the composites fluctuated and deviated from the intensity ratio in bulk. Numerical simulation confirmed this tendency qualitatively.