부산대학교 도서관

We present the effects of organic additives (sucrose, polyvinylalcohol [PVA], and polyvinylpyrrolidone [PVP]) on a precursor solution (VO2+ ion) to the physicochemical properties of the thermally deposited VO2 film on sapphire (0001) plane. All the VO2 films, which deposited with assistance of the organic chemicals, showed a sudden change in resistance measurement near 340 K, but the sudden change did not appear in the film which deposited without the organic additives. The X-ray diffractometer patterns of the films show monoclinic type VO2 (M-VO2) as main phase, which has preferred growing axis (020) and (−211), and V2O5 as impurity phase. The intensity of the impurity peaks was minimized in PVP-assisted deposition and showed the best performance as a smart window, ~10% transmittance gap between low and high temperature phases at 1550 nm. The atomic ratio of oxygen/carbon in the organic additives (1:1 in sucrose –[CH2O]n–, 1:2 in PVA –[C2H4O]n–, and 1:6 in PVP –[C6H9NO]n–) seems an important condition to determine the performance of the smart window.