Theoretical study on the tungsten-induced reduction of transition temperature and the degradation of optical properties for VO2.

We have studied the effect of the doped tungsten on the phase transition temperature and the optical properties between the monoclinic phase and the rutile phase of VO2 by performing first-principles calculations. It is found that the introduction of tungsten (W) significantly decreases the transition temperature between the rutile VO2 and the monoclinic VO2, with reducing the energy difference between the two phases. Meanwhile, our calculations indicate that the doped W lowers the infrared light transmittance of the monoclinic VO2, being consistent with the experimental observations. The nature about the reduction of the transition temperature and the change of the optical properties arising from the W dopants is revealed. Our results are valuable for application of VO2 as an optical energy material in future.