Preparation and optoelectronic properties of vanadium oxide-graphene oxide composite films

Vanadium oxide (VO_x, 1 ≤ x ≤ 2.5)-graphene oxide (GO) composite films were prepared by the combination of spin-coating of VO_x sol-gel and spray-coating of GO dispersion.The physical morphologies, crystallinities, optical and electrical properties of the as-prepared films were systematically characterized by SEM, XRD, ellipsometry, UV-visible spectrometer, FTIR and high resistance meter. The results indicate that the resistivity of the composite film decreases from 108.78 Ω·cm for the pristine VO_x film to 68.64 Ω·cm after GO addition, while the temperature coefficient of resistance(TCR) increases from -1.98%K^-1 to -2.60%K^-1. In addition, VO_x-GO composite film exhibits a higher light absorption. These suggest that the GO addition can significantly improve the performance of VO_x films as thermistor materials. The results present in this work not only provide valuable information for the exploration of novel VO_x-based infrared thermistor materials, but also promote the development of uncooled infrared detectors.