A simple and cost effective sol-gel process for producing vanadium dioxide thin films was developed via thermolysis of V2O5 center dot nH(2)O (n approximate to 2) V-V precursors prepared by dissolving vanadium powder or V2O5 powder in 30% hydrogen peroxide solutions. After spin-coating on fused silica substrates and annealing at 750 degrees C in vacuum, without any intermediate gas reducing step, the major phase VO2(M, monoclinic phase) was found in both of the films based on V-H2O2 and V2O5-H2O2 precursor, exhibiting large transmittance changes (>40%) in the IR region (>2000 nm) and small hysteresis loop width (<5 degrees C) which were comparable to reported epitaxial VO2 films. The two films have similar metal-to-insulator transition temperature tau(C) = 62.5 degrees C, lower than the classical value of 68 degrees C for VO2 thin films. In addition, the method enables simple doping, as found for 0.56 at.% W-doped VO2 films. This intrinsically simple solution process followed by one-step annealing makes it potentially useful in smart window applications. (C) 2013 Elsevier B.V. All rights reserved.