Chameleon photonic crystals: Acid-induced emission and absorption shifts for sensor applications

Abstract

Thanks to their optical properties, photonic crystals are a very interesting group of modern materials. Their applicability is further enhanced by the possibility of doping with stimuli-responsive compounds. This paper presents a preparation and characterization of photonic crystals doped with a luminescent dye – ethyl eosin. By doping with this dye, a material with sensor properties and unique optical properties such as angle-dependent emission was obtained. The study focused on determining the luminescence properties of the opals and the dye, specifically their quantum yield (QY). Moreover, the obtained dye-doped photonic crystals exhibit a rapid change in luminescence properties and color after contact with vapors of inorganic acids commonly used in industry. Furthermore, a three-dimensional opal doped with ethyl eosin exhibits a selective change in the presence of nitric acid(V), unlike the dye solution. These luminescent and sensing properties, coupled with reversibility, make this material fascinating.