Selective hydrogenation of WO3 for erasable conducting circuit.

Hydrogenation of tungsten trioxide (WO3) can effectively modulate its material property and induce the insulator–metal transition. Due to the insertion of H atoms, a transparent WO3 film will normally change to deep-blue color because of its pronounced electrochromism. More importantly, the electronic structure will also convert from an insulator to a metallic state, showing greatly improved conductivity with an enhancement of up to six orders of magnitude. Combined with the traditional lithography route, selective hydrogenation of WO3 in microscale size is achieved based on the electron–proton synergistic effect in an acid solution. This metal-like conductive H-doped WO3 can be used as an erasable microcircuit since it will be recovered to a WO3 insulator by annealing in air at an appropriate temperature. The current study demonstrates a facile way to fabricate erasable WO3 conducting micro/nanowires, or even microcircuits, by selective hydrogenation under ambient conditions, which should be extended to other oxide materials for functional applications. [ABSTRACT FROM AUTHOR]