Design and Synthesis of a Black Photochromic Diarylethene for Bioinspired Display Applications

Black photochromism, in which the photogenerated isomer has an absorption band over the whole visible region, is fascinating for applications such as information display, photochromic solar cells, or smart windows. However, black photochromism in a single organic photochromic component is quite rare. In this study, we tried to design and synthesize a photochromic diarylethene derivative that shows black photochromism in a single molecular backbone. By optimizing the molecular structure of a diarylethene derivative having a functionalized indole ring as the aryl group, we successfully prepared a black photochromic diarylethene derivative, which shows a reversible color change between pale yellow and black along with the photochromic reactions in solution as well as in solid state. Furthermore, with imitating the coloration system of some living organisms, optical patterning was successfully demonstrated based on the photoregulation of the contrast of structural color by changing the background color along with the photochromic reactions.