Small polaron hopping conduction in V2O5-Sb-TeO2 glasses

The dc electrical conductivity of glasses in the system V2O5-Sb-TeO2 prepared by press quenching was studied at 303-473 K. The composition range of the glass formation region was 10 less than or equal to TeO2 less than or equal to 100 mol%, 0 less than or equal to V2O5 less than or equal to 70 mol%, and 0 less than or equal to Sb less than or equal to 20 mol%, resp. The glasses indicated n-type semiconductors from the measurement of thermoelectric power. The dc conductivities at 473 K for the present glasses were 6.38x10-6-7.13x10-3Scm-1, indicating that the conductivity increased with increasing V2O5 concentration. Sb content also contributed to increase the conductivity and decrease activation energy for electrical conduction. A model of redox reaction during melting was proposed and quantitatively explained the reaction between V2O5 and Sb. A glass of composition 70V2O5*20Sb*10TeO2 (mol%) having a conductivity of 7.13x10-3Scm-1 at 473 K was the highest conductive glass among the previous vanadium tellurite glasses. From the conductivity-temperature relation, it was found that small polaron hopping model was applicable at the temperature above 1/2 the Debye temperature. 54 refs.