Fabrication of TiO2: Nb array films and their enhanced electrochromic performance

Abstract

In this work, Nb-doped TiO2 (NTO) array films were prepared on indium tin oxide (ITO) glasses via laser interferometry combined with the photosensitive sol–gel technique. The electrochromic properties of the NTO film with smooth surface and the one with array structure were compared. The results reveal that the both kinds of films have the property of selectively and independently spectral control over optical transmittance in the Visible (Vis) and near-infrared (NIR) regimes. Moreover, the NTO array film exhibits more superior electrochromic performance. The optical contrast of the NTO array film is 19.68% (in the NIR region) and 9.58% (in the Vis region) higher than that of the NTO film. The coloring time (tc) and bleaching time (tb) are tested to be 17 s and 3 s, which shortened 9 s and 4 s compared to NTO film. The enhanced electrochromism originates from the enhancement of the local surface plasmon resonance (LSPR) of the array.