Multicolor Bipolar Modulation of Titanium–Chromium Oxide Electrochromic Coatings

Abstract

Electrochromic (EC) materials offer wide-ranging commercial applications, including smart windows, electrochromic mirrors, and programmable static displays. While many conventional electrochromic applications require the encapsulation of the EC materials and other components inside a sealed cell, there are cases where the color appearance of the object’s surface needs to be durable in atmospheric or aquatic environments. Among the current fabrication methods for EC materials, atomic layer deposition (ALD) remains less explored. In this work, we fill these gaps by employing ALD to grow a (Ti,Cr)O x film as a new subset of EC coatings that operates in direct contact with aqueous solutions. The protective and bipolar coloration properties of the (Ti,Cr)O x are achieved by the ALD alloying of TiO2 and CrO x nanocrystals. Intrinsic EC performance showed excellent cycle stability of more than 2000 cycles in aqueous electrolytes of high salinity and high corrosion resistance in pH = 0 acid. Furthermore, multicolor modulation has been achieved via a Fabry–Perot optical cavity design. Microstructural and spectroscopic characterizations combined with finite-difference time-domain (FDTD) modeling allow us to correlate the optical appearance with coating electronic and microstructures. This work showed that this ALD-grown ternary EC coating can also act as a surface protection layer and has unique advantages over other EC materials to achieve balanced performance among color tunability, coloration efficiency, and cycle stability.

Photocatalytic CO2 Reduction with Dissolved Carbonates and Near-Zero CO2(aq) by Employing Long-Range Proton Transport

“…Photo-generated electrons transport to and accumulate at the Ag reductive sites to facilitate CO 2 R, while photo-generated holes are separated from the electrons and transport to and through the TiCrO x coating and eventually accumulate at the coating surface sites (where no Ag on top) to facilitate H 2 BQ or EtOH oxidation . For oxidative redox processes, hole charges transport through a 3 nm-thick TiCrO x coating effectively due to the energetic alignment between the GaInP 2 valence band and TiCrO x intermediate band …”

“…Journal of the American Chemical Society alignment between the GaInP 2 valence band and TiCrO x intermediate band. 29 Meanwhile, dissolved CO 2 molecules, including dissolved CO 2 (aq) and the local CO 2 generated from in situ HCO 3 − protonation, are transported to Ag nanoparticles, adsorb, and participate in charge-driven CO 2 R catalysis at the Ag active sites. The products, e.g., CO(g), desorb and get collected in the gas headspace and detected by a gas chromatograph (GC), which also monitors other gaseous products such as H 2 .…”

Structural Color Boosted Electrochromic Devices: Strategies and Applications

“…The UV‐patterned PEDOT:Tos device could be applied for switchable color displays (Figure 4g). Moreover, Shen and coworkers [ 78 ] deposited the EC material (Ti, Cr)O x on a thin metallic Ir film by atomic layer deposition and observed a rich color palette by varying the thickness of the alloyed oxide coating or applied bias.…”