Optical fiber sensor for dual sensing of temperature and oxygen based on PtTFPP/CF embedded in sol-gel matrix

A simple, low cost technique to fabricate a plastic optical fiber sensor for dual sensing of temperature and oxygen has been described. The optical fiber dual sensor consists of temperature and oxygen indicators that were coated on the fiber end. A fluorinated xerogels doped with platinum tetrakis pentrafluoropheny porphine (PtTFPP) and 5(6)-carboxyfluorescein (CF) serves as the oxygen and temperature sensing material. The temperature and oxygen indicators can both be excited with an LED of 405 nm, and the two emission wavelengths can be detected separately. The optical fiber dual sensor has been tested with regard to monitoring different temperatures and oxygen concentrations. The typical Stern-Volmer plot of an optical fiber dual sensor for oxygen sensing shows linearity, and the attenuation of the relative luminescence intensity for temperature sensing also has a linear relationship with temperature in the tested range. In addition, our results show that the luminescence properties of the temperature sensor are independent of the presence of the oxygen sensor, and have a uniquely good linear response in the 25-66 °C range. Finally, the oxygen sensing scheme presented in this work is intended for use in temperature compensation, and optical fiber dual sensor can be used for the contactless-sensing of temperature and oxygen in biological, medical and environmental applications.