Luminous relative humidity sensing by anionic fluorescein dyes incorporated into layered double hydroxide/1-butanesulfonate hybrid materials

[Display omitted] Spectroscopic properties of solid relative humidity (RH) sensors consisting of anionic fluorescein dyes (AFD) and 1-butanesulfonate (C4S) ions hybridized with layered double hydroxides (LDH) were investigated under various RH conditions. The obtained LDH/C4S/AFD hybrid material contained at least three different types of water adsorption sites with adsorption capacities of one water molecule per formula unit. Photoluminescence (PL) intensity of the LDH/C4S/AFD hybrid was significantly enhanced by water adsorption (especially in the RH range between 20 and 80%) indicating that the synthesized material possessed strong RH sensing properties and thus could be used in water vapor sensor devices.