Photoluminescent polymer electrolyte based on agar and containing europium picrate for electrochemical devices

Dispersion of photoluminescent rare earth metal complexes in polymer matrices is of great interest due to the possibility of avoiding the saturation of the photoluminescent signal. The possibility of using a natural ionic conducting polymer matrix was investigated in this study. Samples of agar-based electrolytes containing europium picrate were prepared and characterized by physical and chemical analyses. The FTIR spectra indicated strong interaction of agar OH and 3,6-anhydro-galactose CO groups with glycerol and europium picrate. The DSC analyses revealed no glass transition temperature of the samples in the −60 to 250 °C range. From the thermogravimetry (TG), a thermal stability of the samples of up to 180 °C was stated. The membranes were subjected to ionic conductivity measurement, which provided the values of 2.6 × 10−6 S/cm for the samples with acetic acid and 1.6 × 10−5 S/cm for the samples without acetic acid. Moreover, the temperature-dependent ionic conductivity measurements revealed both Arrhenius and VTF models of the conductivity depending on the sample. Surface visualization through scanning electron microscopy (SEM) demonstrated good uniformity. The samples were also applied in small electrochromic devices and showed good electrochemical stability. The present work confirmed that these materials may perform as satisfactory multifunctional component layers in the field of electrochemical devices.