Nanostructured p-type Cr/V2O5 thin films with boosted thermoelectric properties

Abstract

The urgent need for non-toxic and abundant thermoelectric materials has become a significant motivation to improve the figures of merit of metal oxides in order to remove the barrier towards their widespread use for thermoelectric applications. Here we show the influence of a Cr layer in boosting the thermoelectric properties of vanadium pentoxide (V₂O₅) thin films, deposited by thermal evaporation and annealed at 500 °C. The Cr to V₂O₅ thickness ratio controls the morphological and thermoelectric properties of the thin films produced. The optimized Seebeck coefficient and power factor values at room temperature are +50 μV K⁻¹ and 7.9 × 10⁻⁴ W m⁻¹ K⁻², respectively. The nanograin structure of the films is responsible for an improvement in the electrical conductivity up to 3 × 10⁵ (Ω m)⁻¹ with a typical thermal conductivity of 1.5 W m⁻¹ K⁻¹. These results combine to yield promising p-type thermoeletric CrV₂O₅ thin films with a ZT of 0.16 at room temperature.