Heterophenoquinones: Tuning Optoelectronics and Electrochromicity

Abstract

AbstractWe report the synthesis and optoelectronic properties of 16 thiophene‐based heterophenoquinones. These compounds were accessed in a convergent and modular approach, allowing for their efficient synthesis. Tuning of the optical band gap was achieved through π‐extension by annulation of a benzene or tropone moiety to the thiophene, oxidation, change of the heteroatom or by attachment of a donor substituent to the thiophene core. The resulting compounds display intense colors covering the entire visible spectrum. We identified structure‐property relationships and their impact on the HOMO and LUMO levels. Additionally, these materials change color upon reduction and according to in situ ultraviolet‐visible‐near infrared (UV‐vis‐NIR) and electron paramagnetic resonance (EPR) spectro‐electrochemistry, they are promising electrochromes with cathodic color changes. Seven different electrochromic devices were constructed which all displayed a change in color upon reduction, demonstrating the potential of these new dyes in for example tintable glass.