Optical characterization of the coloration process in electrochromic amorphous and crystalline WO3 films by spectroscopic ellipsometry

Ion-Transport Design for High-Performance Na+-Based Electrochromics

“…The switching time of MOFs is generally characterized as the period required for 90% of the optical change between the bleached and colored states to occur and is a crucial parameter for EC devices. As expected, the Na + -based colored and bleached times of the Ni-CHNDI film at 720 nm were calculated to be 2.1 and 1.9 s (Figure c), which were much faster than reported Na + -based EC materials and other EC MOFs in traditional TBA + - and Li + -based electrolytes (Table S4, Supporting Information) and also comparable with other cation intercalation EC systems. ,− TBA + -, Li + -, and Al 3+ -based switching times for the Ni-CHNDI film were 4.8 s/4.1 s, 9.1 s/4.9 s, and 11.6 s/9.1 s, i . e ., slower than that of Na + because of the poorer diffusion kinetics in the channels.…”

Recent progress and advances in electrochromic devices exhibiting infrared modulation

“…According to previous studies, the crystallinity of WO 3 plays a very important role in determining the electrochemical and optical properties. [118][119][120] Both crystalline and amorphous WO 3 possess EC performance upon ionic insertion but show different behaviors in the coloration and bleaching process. Amorphous WO 3 (a-WO 3 ) features a fast response time and high coloring efficiency due to the disordered arrangement of the octahedron in the structure, which provides open polygonal voids for ion transport.…”

Mimicking Nature's Butterflies: Electrochromic Devices with Dual‐Sided Differential Colorations

“…In addition, the complex refractive index of WO 3 can be effectively altered by applying negative voltages, [32,33] which can further modulate the asymmetric colors of these devices (Figure S19a,bii, Supporting Information). The changes in the optical parameters (n, k) of the WO 3 layer account for the blue-shift of the reflected colors and the decreasing lightness of the Janus-structured electrochromic devices observed from the film side, which is also confirmed by the measured and simulated reflectance spectra (Figure 5e; Figures S20b,d, Supporting Information).…”

“…As expected, the color of the substrate side of devices with 260 nm ITO layers also shifts toward green regions under negative voltages (Figure S23, Supporting Information). As a consequence, Equation (3), for the transfer matrix of the substrate side of the Janus-structured electrochromic devices needs to be rewritten as Equation ( 4), as follows Substrate side: 0 43 3 32 23…”