Chemical structures and physical properties of vanadium oxide films modified by single-walled carbon nanotubes

Abstract

A series of vanadium oxide (VO_x)–single-walled carbon nanotube (SWCNT) composite films with different SWCNT concentrations were prepared and systematically investigated. The results reveal that after SWCNT addition, the optical absorption and electrical conductivity of VO_x are enhanced, but the crystallinity and temperature coefficient of resistance (TCR) are weakened. Consequently, either too low or too high CNT loading will lead to the degradation of the comprehensive properties. In contrast, the VO_x–SWCNT composite film containing 4 wt% SWCNTs exhibits the optimal comprehensive properties such as high film uniformity, large optical absorption, and desirable sheet resistance (141 kΩ) and TCR (−1.73% K⁻¹), favorable for applications in uncooled infrared detectors. Saturated interactions between SWCNTs and VO_x are observed at 6 wt% SWCNTs, after which (≤10 wt% SWCNTs) the structures and properties are changed slightly. This work reveals the modification of the chemical structures and physical properties of VO_x films by SWCNTs, whose results will be helpful not only for a better understanding of VO_x, SWCNTs, and their composites, but also for seeking new versatile functional materials for device applications.