Electrochemical luminescence modulation in a Eu(III) complex-modified TiO2 electrode

Electrochemical modulation of red luminescence from a europium(III) complex has been demonstrated. In order to elucidate the mechanism of luminescence modulation, its cyclic voltammogram, absorption spectra, emission spectra, emission lifetime, and emission quantum yield were measured. From these measurements, the modulation of emission was found to be achieved through an electrochemical reaction of TiO2, which is facilitated by electron transfer between the europium(III) complex and TiO2. Subsequent immobilization of the europium(III) complex on a TiO2 electrode resulted in an on-off emission contrast of 74 : 1, with the response time and repetition stability of the emission switching being considerably improved.