Transition metal complexes for electrochromic and electrofluorochromic devices

Abstract This minireview discusses recent advances in transition metal complexes for electrochromic (EC) and electrofluorochromic (EFC) devices. EC and EFC materials can switch their color and photoluminescence, respectively, through electrochemical redox reactions. Transition metal complexes offer promising opportunities due to their molecular design versatility for various optoelectrical properties. The review provides an overview of electrochromism and electrofluorochromism, including performance characterization methods and device fabrication techniques. It highlights EC transition metal complexes that can form thin films suitable for device applications and EFC transition metal complexes that can efficiently tune photoluminescence through electrochemical quenching mechanisms. The review also summarizes advanced functions of EC/EFC transition metal complexes, including large optical contrast, fast response, dual-switching of color and emission, and easy device fabrication, which could lead to low-cost displays. Overall, this review article presents the latest research on transition metal complexes for EC and EFC devices and their potential for practical applications.