Ultrafast Solid-State Transformation Pathway from New-Phased Goethite VOOH to Paramontroseite VO2 to Rutile VO2(R)

Abstract

Monoclinic vanadium dioxides VO2(M) is prototype material for interpreting correlation effects in solids, and its fully reversible metal−insulator transition (MIT) also brings the great interest in construction of intelligent devices such as temperature sensors and energy-efficient smart windows. The solid-state transformation started from vanadium precursors has been long-term regarded as the classic effective route to rutile VO2(R), while the conventional vanadium precursors usually requires indispensable atomic lattice rearrangement and reshuffling to realize rutile VO2(R) phase, leading to strict experimental conditions, high cost, and long conversion time (even more than one day) during the VO2(R) formation process. Herein, under the theoretical guidance of atomically structural analysis, a new structure-conversion pathway from goethite VOOH to paramontroseite VO2 to rutile VO2(R) realized an alternative ultrafast transformation into desired monoclinic VO2(M), of which each two steps only requires within 60 s. Thanks to the discovered new-phased goethite VOOH, the well-crystalline synthetic paramontroseite VO2 was realized from the chemically synthetic way, and in effect the paramontroseite structure plays the decisive role in achieving the desired monoclinic VO2(M) from the structural viewpoint, which would further promote this expensive material into the realm of conventional laboratory synthesis. The realized monoclinic VO2(M) exhibits the smart switching properties in regulating thermal, magnetic, and near IR light behaviors, and more importantly the metal−insulator transition (MIT) parameters such as the MIT temperature and the width of heating−cooling hysteresis are now precisely controlled. These intriguing findings may pave new way for designing other functional solid materials with correlation effects and then providing the material guarantee for constructing the intelligent devices in future.