Optical sensors, 13: fibre-optic humidity sensor based on fluorescence quenching

Abstract A fibre-optic fluoresensor for the determination of relative humidity is presented. It is based on the quenching of fluorescence of silica-gel-adsorbed perylene dyes by water vapour. The perylene-based sensors show a total signal change of 95% in going from 0 to 100% relative humidity, but the response is not linear. The advantages of this type of sensor are a fairly simple optical system, the use of LED-excitable dyes and a simple method for the preparation of sensor layers. Oxygen, however, interferes in showing some quenching as well.