Studies of opal crystals infiltrated with iron porphyrin

Synthetic opal crystals were infiltrated with concentrated (1-10 mM) aqueous solutions of iron porphyrin (FeTPPS). The assemblies of nanoscale blocks of 25-30 nm, which have been clustered into rod-like structures of size 100-150 nm typical of FeTPPS, were observed on the surface of silica spheres (diameter D∼250 nm). Optical properties of infiltrated photonic crystals were investigated on the samples immersed into liquids. The Q absorption bands of FeTPPS were located in the vicinity of opal stop band, the position of which was tuned by varying the effective refractive index of opal immersed in various liquids. The Q absorption bands of FeTPPS were strongly influenced by ethanol presumably due to the formation of chemical bonds between sulfonic groups of FeTPPS with silanol groups on the surface of silica spheres and with ethoxy groups in ethanol environment. Data have shown that FeTPPS is a perspective material for the development of hybrid magnetophotonic devices based on the opal photonic crystals.