Synthesis and characterization of vanadium and iron tellurite glasses for applications as thermal sensors

Semiconducting transition metal oxide tellurite glasses: xV2O5-(100-x)TeO2 (x = 10, 30, 40, 50 and 55, 60, 65 and 70 mol%), xCuO-50V2O5-(50-x)TeO2 (x = 1, 3 and 5 mol%), xFe2O3-(100-x)TeO2 (x = 10 and 20 mol%) and xFe2O3?45V2O5-(55-x)TeO2 (x = 5 and 10 mol%) were prepared by normal and splat quenching techniques. The thermal, electrical and structural properties of glasses were characterized. The highest electronic conduction is in the xV2O5-(100-x)TeO2 glasses; the room temperature conductivity of this glass series increases from 9.21 ? 10-9 ?- 1m- 1 to 3.30 ? 10- 4 ?- 1m- 1 upon increasing V2O5 concentration from 10 to 70 mol%. Iron tellurite glasses also show a large enhancement of conductivity with an increase in Fe2O3 concentration. The glass transition temperature (Tg) of vanadium tellurite glasses decreases, while those of iron tellurite glasses increases with an increase in V2O5 and Fe2O3 concentrations respectively. The incorporation of Cu and Fe ions in xV2O5(100-x)TeO2 increases Tg significantly but it suppresses the electrical conductivity. Vanadium tellurite glasses show the growth of ?-TeO2 crystals in the glass matrix on irradiation with 488 nm Ar ion laser. Transition metal oxide tellurite glasses have potential application as thermal and body temperature sensors due to their large temperature coefficient of resistance in the range of -3.04 to -2.26% K-1.