Chromogenic materials and devices : Influence of the nature, stoichiometry and shaping of materials

Aline Rougier^1*

¹cnrs, icmcb, Pessac, France

* Presenter:Aline Rougier, email:aline.rougier@icmcb.cnrs.fr

Chromogenic materials exhibit tunable properties as a consequence of an external stimulus such as light (photochromism), temperature (thermochromism) or potential (electrochromism..). Those smart compounds find applications in buildings and automobile industry by controlling light and heat transfer through windows for transmissive devices while colour changes in reflective devices offer great interest in the field of displays and printed electronics. In this presentation, through various examples, we will illustrate the key role played by the synthesis or/and the deposition route on the physico-chemical properties of mostly oxides powders and thin films as well as on their chromogenic properties. In particular, multichromism, namely thermochromism and electrochromism, in vanadium oxides will be discussed in respect of the oxide stoichiometry. Beside the influence of shaping in form of nanopowders synthesized through the polyol process [1] or of thin films of few hundred nanometers grown by RF sputtering method or thick films of few micrometers by doctor blading on the chromogenic properties will be illustrated focusing more specifically on electrochromism (V2O5) and thermochromism (VO2) [2]. In addition, of the single layer characterization, the optimization of the architecture of the ECD multilayer device, also described as an optical battery, will be discussed in respect of the nature of the transparent conducting layer as well as of the electrolyte.
[1] I. Mjejri et al., Inorg. Chem., Low-Cost and Facile Synthesis of the Vanadium Oxides V2O3, VO2, and V2O5 and Their Magnetic, Thermochromic and Electrochromic Properties, 56 (2017) 1734−1741
[2] I. Mjejri et al., From the Irreversible Transformation of VO2 to V2O5 Electrochromic Films Inorg. Chem., in press 2022 DOI: 10.1021/acs.inorgchem.2c02722
[3] C. Périé et al., Colored electrolytes for electrochromic devices, Sol. En. Mat. Sol. Cell, 2022, 238, 111626

Keywords: Chromogenic Materials, Architecture of Devices, Oxides, Electrochemical properties, Optical Properties