Electrochromic property of the viologen-anchored mesoporous TiO2 films

Abstract

The electrochromic properties of the viologenanchored mesoporous TiO 2 (Meso-TiO 2 ) films were investigated in this work. The Meso-TiO 2 films, synthesized by evaporation-induced self-assembly (EISA) process, deposited on ITO electrodes were a worm-like structure with an average pore diameter of 7.0 nm. The electrochromic devices (ECDs) fabricated from the Meso-TiO 2 demonstrated 3 times of coloration efficiency and considerably faster switching response, compared with those from the nanocrystalline films made of the 7 nm-sized TiO 2 nanoparticles. The advantage of the Meso-TiO 2 would originate from the well-organized mesopore structures, offering an efficient electrolyte transport as well as the fast electron transfer from the ITO electrode to the anchored viologen.

Block copolymer-templated synthesis of highly organized mesoporous TiO2-based films and their photoelectrochemical applications

“…Currently various heat-resistant substrates such as Pyrex glass [16,17,45,66], fused silica [51], transparent conductive oxide (TCO) [67][68][69][70][71], quartz [46], stainless steel [72][73][74], Ti foil [50], and silicon [15,75,76] have been employed for film deposition. The nature of coating substrates, particularly the surface roughness, has found to exert an influence on the mesostructural regularity of the mesoporous TiO 2 films [77].…”

Solid‐State Electrochromic Devices via Ionic Self‐Assembled Multilayers (ISAM) of a Polyviologen

“…The dark violet color remains during the reduction scan between À0.6 to À0.85 V, but changes to pale yellow due to the doubly reduced viologen at potentials higher than À0.9 V. The second reduction peak, which corresponds to the yellow color, was not observed in the current CV scan of potential window from 0 to À1.0 V, but has been observed by several other groups at À1.0 V or higher for scan rates of 10 mV Á s À1 or slower. [31] During the oxidation scan, the color changes from pale yellow to dark violet and finally back to original transparent state. Both reduction and oxidation peak current densities increase with the scan rate; this confirms that the reaction is diffusion controlled but slow ( Figure 5).…”

Titanium phosphates as positive electrode in lithium-ion batteries: composition, phase purity and electrochemical performance

“…Mesoporous materials have taken extensive attention due to their involvement in diversity of applications including, for example, catalysis [3,4], sensors [5,6], host materials for lithium-ion storage [7][8][9][10], hydrogen production [11,12] and storage [13,14], electrochromic windows [15,16], and dye-sensitized solar cells [17][18][19].…”