Blue LED Excitable Temperature Sensors Based on a New Europium(III) Chelate

A new europium(III) chelate is synthesized and characterized. The wavelength of sensitization of Eu³⁺ luminescence is shifted further into visible so that efficient excitation with 425, 435 and 450-nm LEDs becomes possible. Photophysical properties and temperature dependence of luminescence are investigated in toluene solution and various polymer matrixes. The sensor materials are also characterized in terms of cross-sensitivity to oxygen and photostability. The sensor material based on the europium complex immobilized into poly(vinylidene chloride-co-acrylonitrile) shows negligible cross-sensitivity to oxygen and is particularly attractive for applications at physiological conditions. Other materials can be applied for sensing and imaging purposes at room temperatures. The new materials can also be used for compensating optical (oxygen, CO₂ etc.) sensors for temperature effects.