Emission spectra of the sol–gel glass doped with europium(III) complexes of picolinic acid N-oxide—A new UV-light sensor

New europium complexes of picolinic acid N-oxides have been synthesised and introduced into sol–gel matrices. Their application as UV-light sensors has been considered. The sequence of the electronic levels for Eu3+ ions has been determined from the absorption and emission studies and assigned to the respective electron transitions. The lifetimes of the excited states have been detected and analysed. The role of the CT transition inside the picolinic ligand and its influence on the ligand to metal charge transfer (LMCT) have been discussed.