Vanadium dioxide (VO 2 ) undergoes a fully reversible first-order metal− insulator transition from the M1 monoclinic phase (P2 1 /c) to a high-temperature tetragonal phase (P4 2 /mnm) at around 68 °C. Modulation of the phase transition of VO 2 by chemical doping is of fundamental and technological interest. Here, we report the synthesis of highly crystallized Fe-doped VO 2 powders by a carbo-thermal reduction process. The impact of Fe doping on the structural and phase transition of VO 2 is studied. The as-prepared Fe-doped VO 2 samples crystallize in the M2 monoclinic form (C2/m), which is linked to segregation of the doping ions in the V2 zigzag chains. A large increase in the transition temperature to 134 °C is observed, which does correspond to a breakthrough in VO 2 -type thermochromic materials.

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