Controllable Phase Transition Properties in VO Films via Metal-Ion Intercalation.

VO has shown great promise for sensors, smart windows, and energy storage devices, because of its drastic semiconductor-to-metal transition (SMT) near 340 K coupled with a structural transition. To push its application toward room-temperature, effective transition temperature () tuning in VO is desired. In this study, tailorable SMT characteristics in VO films have been achieved by the electrochemical intercalation of foreign ions (e.g., Li ions). By controlling the relative potential with respect to Li/Li during the intercalation process, of VO can be effectively and systematically tuned in the window from 326.7 to 340.8 K. The effective tuning could be attributed to the observed strain and lattice distortion and the change of the charge carrier density in VO introduced by the intercalation process. This demonstration opens up a new approach in tuning the VO phase transition toward room-temperature device applications and enables future real-time phase change property tuning.