Emission of opal photonic crystals filled with europium and terbium

Abstract

This paper presents measured emission spectra of opal photonic crystals filled with rare-earth phosphors. We obtained photoluminescence spectra of the (111) growth surface of an opal photonic crystal whose pores were filled with sols containing nanoparticles of rare-earth compounds (Eu3+ and Tb3+) in amounts within 30 ppm. Ultraviolet excitation was provided by light emitting diodes operating at wavelengths of 366, 382, and 410 nm and by the fourth harmonic of a Nd:YAG solid state laser (λ = 266 nm). The obtained results lead us to conclude that the lasing threshold can be lowered for transitions of the rare-earth ions. Under illumination with narrow-band light sources, we observed electromagnetic radiation conversion to the band gap region of the photonic crystal. Opal photonic crystals filled with rare-earth ions are potentially attractive for improving solar cell efficiency.