摘要
To meet the development of wearable and energy-efficient flexible electronics, multifunctional oxide film on soft substrate and its versatile phase control are in demand. Here, flexible VO <sub>2</sub> film is directly deposited on mica via van der Waals epitaxy, exhibiting pronounced metal-insulator (MI) transition and infrared (IR) switching properties. Using a rubbery solid ionic gel as gate insulator, a fully flexible and transparent VO <sub>2</sub> -channel Mott transistor is successfully demonstrated. The prototype Mott transistor processes excellent mechanical flexibility and giant on/off current ratio of ≈10 <sup>5</sup> % even at room temperature. Highly reversible suppression of MI transition is realized by applying small gate voltages and the nonvolatile phase modulation suggests an electrochemical reaction mechanism. X-ray diffraction and secondary-ion mass spectroscopy analyses, together with theoretical calculation, confirm that electrically controlled phase transformation is mainly caused by reversible and nonvolatile proton (H <sup>+</sup> ) doping into VO <sub>2</sub> lattices. Significant modulation of IR transmittance (>40%) is observed in the VO <sub>2</sub> Mott transistor, which is attributed to electrically driven phase transition between insulating VO <sub>2</sub> and metallic H <sub>x</sub> VO <sub>2</sub> phases. The flexible and transparent Mott transistor provides a good platform for proton-mediated Mottronics and realizes novel electric control of optical characteristics, showing a promising application for flexible energy-saving smart windows.