Realizing UltrafineColor Tuning of Organic ElectronicsMaterials by Electronic State Informatics

Organic electrochromic (EC) materials enabling energy-efficient smart windows, human-friendly displays, and highly transparent medical lenses are key for a future society. However, developing organic EC molecules that change from transparent to pure magenta, one of the three primary colors, had been impossible through simple quantum chemical calculations and experiments alone, as it requires sophisticated spectral optimization involving multiple electronic transitions in neutral and radical states. In this study, we successfully identified structures exhibiting colorless-to-pure-magenta switching from 1.2 million triphenylamine derivatives using electronic state descriptors easily obtained from semiempirical molecular orbital calculations with qualitative accuracy. Subsequent organic synthesis and spectroelectrochemical experiments proved that the identified candidate molecules achieve the desired functionality.