Development and studies of electrochromic and electrofluorochromic organic materials
Organic electrochromic materials have been a hot area of research during the past decades. These compounds that respond to an applied potential with a color change are said to be electrochromic. Their interest is mainly because of the easy synthesis, convenient mass production, and eco-friendly preparation compared to their inorganic counterparts. Typically, these compounds change only their color with an applied potential. To develop compounds that change both their color and their fluorescence with a potential applied for use in electrofluorescent devices remains a major challenge. In this study, a series of compounds containing triphenylamine (TPA) and benzothiadiazole (BZT) were evaluated. They were coupled with different end groups to tune the photophysical and electrochemical properties. These compounds were fully characterized by absorption spectroscopy, fluorescence spectroscopy, cyclic voltammetry, spectroelectrochemistry, and X-ray diffraction along with other techniques. This allowed us to examine the influence of their structure on the properties. It also allowed us to identify the ideal compounds of interest for use in functioning devices. The devices containing TPA and BZT are ideally ‘smart window’ applications. This is due to the electrochemical activity by TPA as well as the solid state fluorescence of the BZT core. To further improve the properties of devices, a passive device was the ultimate goal. This is in contrast to active devices where a potential must be applied continuously for the induced color to be consistent. Towards this goal, cathodic layers were prepared and investigated in a device and their use as an ion reservoir in a passive electrochromic / electrofluorescent device was tested. Preliminary results, showed that anthraquinone derivatives had ideal properties for the cathodic layers.
Benzothiadiazole Anthraquinone Electrochromism Triphenylamine Smart Window