Effect of nanocrystallization on the structural and electrical conductivity enhancement of vanadium-based glasses

A new glass–ceramic nanocomposites material was prepared by a thermal nanocrystallization of V₂O₅–Bi₂O₃–P₂O₅ system with different V₂O₅ content. The amorphous state of glassy materials is confirmed by X-ray diffraction. It was shown by XRD and SEM studies that by suitable heat-treatment glasses can be turned into glass–ceramic nanocomposites consisting of crystallites smaller than 80 nm inserted in the glassy matrix. Also, it was shown that thermal nanocrystallization of as-prepared glassy samples leads to creation of nanocrystalline grains of V₂O₅, Bi₂O₃, and BiVO₄ phases. The glass–ceramic nanocomposites obtained show giant enhancement of electrical conductivity than the as-prepared glasses. The conductivity enhancement was recognized to interfacial regions adjacent crystalline grains. The conduction of the present glasses and their glass–ceramic nanocomposites was confirmed to be due to primarily non-adiabatic hopping of small polaron between vanadium ions.