Improvement of Electrochromic Performance by Embedding ITO Nanocrystals in Amorphous WO₃ Film

Abstract

The electrochromic films featuring the well dispersed ITO nanocrystal (about 10 nm) in amorphous WO 3 (ITO@WO 3 ) have been successfully fabricated with a solution process. The structure and electrochromic properties of the as-prepared films were studied by high resolution transmission electron microscope, scanning electron microscope, X-ray photoelectron spectroscopy, X-ray diffraction, and electrochemical methods. The measured coloration/bleach time decreases from 10.5/27.8 s to 5.7/0.9 s with the increasing of ITO/AMT ratio indicating that embedded ITO nanocrystals induce the nanocrystal/glassy interface effect remarkably improving the ion diffusion coefficient and electrochemical activity. The optimal T at 633 nm of 0.1 ITO@WO 3 films is about 53.80% much higher than that of pure WO 3 (about 42.09%). But in near-infrared (NIR) range the pure WO 3 films show the best transmittance modulation rather than the composite films. The above stated results are indicative that the interface effects of embedded ITO nanocrystals play the key role while its plasmon-induced electrochromic effects are limited because of not only excellent NIR modulation capability of amorphous WO 3 itself but also the relative large size of ITO nanocrystals used, demonstrating that smaller nanocrystal size (∼5 nm) are required for better electrochromic performance of the composite films.

Boosting Transport Kinetics of Ions and Electrons Simultaneously by Ti3C2Tx (MXene) Addition for Enhanced Electrochromic Performance

“…The calculated diffusion coefficients of Li + insertion are 2.78 × 10 −11 and 1.80 × 10 −11 cm 2 s −1 with and without MXene addition, respectively. Also, diffusion coefficients of Li + extraction are 1.04 × 10 −10 and 5.52 × 10 −11 cm 2 s −1 with and without MXene addition, which show the quantitative agreement with the previous studies [ 63 , 64 ]. The lithium ion insertion/extraction speed into the electrochromic film is evidently enhanced by the addition of MXene.…”

Enhanced electrochromic properties of WO3/ITO nanocomposite smart windows

“…4(b), the optical modulation rate Δ T is up to 87.89% at wavelength 633 nm, which is higher than many reported electrochromic devices. 10,29–31 As illustrated in Table 1, the optical modulation has reached 90.28% around wavelength 749 nm. Fig.…”

Electrochromism of W–In oxide thin films: Implications for cycling durability

“…Here we report results from a study of In-containing WO3 thin films prepared by codeposition and demonstrate that the In content tends to deteriorate the electrochromism of WO3, thus giving clear evidence that SEI layers are the prevalent source of the boosted cycling durability of potentiostatically pretreated EC WO3 films. We are not aware of earlier work on EC W-In oxide films with metal ions being intermixed on an atomic or near-atomic scale, as in the present investigation; however, studies have been reported on nanocomposites of ITO embedded in WO3 [11][12][13][14][15][16] wherein ITO contributes to optical modulation rate (due to lowered electrical resistance) and modulation range (due to plasmonic effects [17][18][19][20]).…”