Hangchuan Zhang

A rapid-response electrochromic device with significantly enhanced electrochromic performance

A novel electrochromic device (ECD) was constructed with two same-material electrochromic layers deposited on indium-tin oxide (ITO)-coated glass substrates, a double-sided ITO-coated glass substrate, and a gel electrolyte. The device exhibited fast coloration/bleaching response and significantly enhanced optical modulation and coloration efficiency compared to traditional ECDs.

Improved Electrochromic Performance of Poly(3,4-ethylenedioxythiophene) by Incorporating a Three-Dimensionally Ordered Macroporous Structure

In this paper, three-dimensionally ordered macroporous (3DOM) poly(3,4-ethylenedioxythiophene) (PEDOT) films were electropolymerized from an ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim]PF6 ). The electrochromic performances of the 3DOM PEDOT films were studied. The 3DOM films exhibited high transmittance modulation (41.2 % at λ=580 nm), high ionic fast switching speeds (0.7 and 0.7 s for coloration and bleaching, respectively), and enhanced cycling stability relative to that exhibited by the dense PEDOT film. The relationship between the declining behavior of the transmittance modulation and the nanostructure of the film was investigated. A three-period decay process was proposed to understand the declining behavior. The 3D interconnected macroporous nanostructure is beneficial for fast ion and electron transportation, high ion accessibility, and maintenance of structure integrity, which result in enhanced cycling stability and fast switching speeds.

Three dimensional molybdenum oxide/polyaniline hybrid nanosheet networks with outstanding optical and electrochemical properties

3D MoO3/PANI hybrid nanosheet networks were fabricated via hydrothermal, freeze-drying and electropolymerization methods. The structure, morphology, optical and electrochemical properties of the hybrid material were characterized using scanning electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and electrochemical measurements. It was found that the conductivity of the 3D MoO3 nanosheet networks was enormously enhanced by introducing PANI. The 3D MoO3/PANI hybrid nanosheet networks show a complementary dual-electrochromic effect (ranging from light yellow to purple then dark blue), fast switching speed of bleached and colored states (0.9 and 1.0 s, respectively), superior coloration efficiency and better cycling stability. The results demonstrate that optical and electrochemical properties of 3D MoO3/PANI hybrid nanosheet networks were improved compared to those of 3D MoO3 nanosheet networks. The unique inorganic–organic hybrid nanosheet networks can be used as effective electrode materials in the optical–electrochemical field.

Improved Electrochemical Cycling Durability in a Nickel Oxide double layer film

For the first time, a crystalline-amorphous double-layered NiOx film has been prepared by reactive radio frequency magnetron sputtering. This film has exhibited improved electrochemical cycling durability, whereas other electrochromic parameters have been maintained at the required level, namely, a short coloration/bleaching time (0.8 s/1.1 s) and an enhanced transmittance modulation range (62.2 %) at λ=550 nm. Additionally, the double-layered film has shown better reversibility than that of amorphous and crystalline single-layered films.

Review: recent progress in ordered macroporous electrochromic materials

Electrochromic (EC) materials have the ability to change their optical properties when exposed to a low electrical voltage. They have found a wide range of applications in smart windows, low-power displays, and spacecraft thermal control. To improve the practical applicability of EC materials, rational design and exploration of their architectures play a crucial role. Among various architectures, forms of inverse opal structure including two dimensionally and three dimensionally ordered macroporous structure (2DOM and 3DOM) exhibit outstanding and specific performance. In this review, several examples of 2DOM and 3DOM EC materials with detailed preparation methods are presented, followed by a detailed discussion of various aspects in ordered macroporous structural EC films, including common features, structure transition and photonic band gap tuning. In addition, the typical five layered design for the EC material-based device is given, as the device is of the most importance in researches as well as applications. Finally, conclusions and outlook are provided at the end of this review.