Semiconducting properties of cold sintered V 2 O 5 ceramics and Co-sintered V 2 O 5 -PEDOT:PSS composites

Abstract Recently we established a sintering approach, namely Cold Sintering Process (CSP), to densify ceramics and ceramic-polymer composites at extraordinarily low temperatures. In this work, the microstructures and semiconducting properties of V 2 O 5 ceramic and (1-x)V 2 O 5 -xPEDOT:PSS composites cold sintered at 120 °C were investigated. The electrical conductivity (25 °C), activation energy (25 °C), and Seebeck coefficient (50 °C) of V 2 O 5 are 4.8 × 10 −4  S/cm, 0.25 eV, and −990 μV/K, respectively. The conduction mechanism was studied using a hopping model. A reversible metal-insulator transition (MIT) was observed with V 2 O 5 samples exposed to a N 2 atmosphere, whereas in a vacuum atmosphere, no obvious MIT could be detected. With the addition of 1–2 Vol% PEDOT:PSS, the electrical conductivity (50 °C) dramatically increases from 10 −4 to 10 −3  ∼ 10 −2  S/cm, and the Seebeck coefficient (50 °C) shifts from −990 to −(600 ∼ 250) μV/K. All the results indicate that CSP may offer a new processing route for the semiconductor electroceramic development without a compromise to the all-important electrical properties.