Photonic Drying/Annealing: Effect of Oven/Visible Light/Infrared Light/Flash-Lamp Drying/Annealing on WO₃ for Electrochromic Smart Windows

Abstract

In modernization, the electrochromic smart windows are potentially in focus due to their effective control of solar energy by changing the optical modulation in response to an external electric field, thus possibly reducing power consumption. Besides, the efficient way of improving the crystallization of WO3 leads to significant improvement in the electrochromic performance of energy management applications. Herein, the WO3-based electrochromic films were fabricated by the sol–gel process along with controlling the crystallization of WO3 by a photonic drying procedure. The results of the controllable sintering procedure were compared with those of the traditional oven drying method. Among these drying/annealing techniques, the visible-light-drying procedure gave a superior performance with better optical contrast and fast switching behavior. Moreover, the structural features of WO3 were studied through X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy studies. Additionally, the long-life stability (10 000 cycles) of the prepared devices was studied, and visible-light-dried devices showed long-life cycle stability (10% loss from its initial performance) compared with oven/IR light/flash-lamp-dried electrochromic smart window devices.

Enhanced Photocatalytic Production of H2O2 through Regulation of Spatial Charge Transfer and Light Absorption over a MnIn2S4/WO3 (Yb, Tm) Z-Scheme System

“…The high-resolution XPS spectra of W, O, Yb, Tm, Mn, In, and S elements are shown in Figure b–h. In the W 4f XPS spectrum, the characteristic peaks at 35.2 and 37.3 eV are attributed to W 6+ , and the characteristic peaks at 34.8 and 37 eV are assigned to W 5+ . − In Figure c, the O 1s spectrum is deconvoluted into two characteristic peaks at 530 and 531.5 eV, which are attributed to the W–O bond and surface hydroxyl groups, respectively. , As shown in Figure d, the characteristic peaks at 188.7 and 189.2 eV correspond to Yb 4d 3/2 and Yb 4d 5/2 , respectively, , , and the characteristic peak at 178.9 eV of Tm 4d is observed in Figure e, , indicating the doping of Yb and Tm elements in the photocatalyst system. The Mn 2p spectrum is displayed in Figure f and presents the characteristic peaks attributed to Mn 2+ (640.9 and 652.5 eV) and Mn 4+ (644.3 and 653.7 eV). , The In 3d characteristic peaks (Figure g) at 444.4 (In 3d 5/2 ) and 452 eV (In 3d 3/2 ) demonstrate the chemical state of In 3+ . , The energy difference between S 2p 1/2 (162.2 eV) and S 2p 3/2 (161 eV) in Figure h is calculated as 1.2 eV, revealing S 2– in the hybrid photocatalyst. , As shown in Figures S3 and S4, in comparison with those of WO 3 , the XPS spectra of W and O elements of MnIn 2 S 4 /WO 3 and MnIn 2 S 4 /WO 3 (10Yb, 5Tm) – 1 have no obvious change, indicating the great stability of WO 3 without etching/defect formation during the hydrothermal synthesis of the composite photocatalytic system.…”

Review on recent progress in WO3-based electrochromic films: preparation methods and performance enhancement strategies

“…There are various kinds of methods to fabricate WO 3 EC films, such as magnetron sputtering, 56,66–72 sol–gel, 49,51,73–83 hydrothermal, 37,84–87 electrodeposition, 14,88–91 inkjet printing, 92 self-assembly, 42,93,94 chemical vapor deposition (CVD), 95,96 vacuum evaporation, 53,97–102 and so on. The structure and EC performance of the WO 3 films have obvious differences resulting from the various preparation methods and conditions.…”

Pivotal Role of the Granularity Uniformity of the WO3 Film Electrode upon the Cyclic Stability during Cation Insertion/Extraction

“…For WO 3 films, the cyclic failure is generally attributed to the following two aspects: (1) electrochemical failure due to irreversible injection and massive accumulation of Li ions in the film [ 25 ]; and (2) volume expansion during cation injection/extraction, resulting in mechanical cracking of the film [ 26 ]. Either way, improving cyclic stability requires delicate design of the film electrode, where morphology of the WO 3 film is the most important both for the electrochemical performances and the cyclic stability, which has been continuously optimized through modulating the heat-treatment temperature [ 27 ], the annealing method [ 28 ], preparation parameters [ 29 , 30 ], the crystallization, and nanostructures [ 31 , 32 ]. As a matter of fact, in the whole electrochemical field, morphology design and regulation has always been the primary way to improve electrode performances and the cyclic stability [ 33 , 34 , 35 ].…”

“…As a matter of fact, in the whole electrochemical field, morphology design and regulation has always been the primary way to improve electrode performances and the cyclic stability [ 33 , 34 , 35 ]. The common standing is that electrodes with high porosity or extensive grain boundaries are preferred, as they support rapid cation insertion/extraction [ 28 , 36 ]. However, optimization of the electrode morphology should be comprehensively balanced between the electrochemical characters and the cyclic stability.…”