A multicolour bistable electronic shelf label based on intramolecular proton-coupled electron transfer

Bistable electrochromic materials have been explored as a viable alternative to reduce energy consumption in display applications. However, the development of ideal bistable electrochromic displays (especially multicolour displays) remains challenging due to the intrinsic limitations associated with existing electrochromic processes. Here, a bistable electrochromic device with good overall performance—including bistability (>52 h), reversibility (>12,000 cycles), colouration efficiency (≥1,240 cm 2 C −1 ) and transmittance change (70%) with fast switching (≤1.5 s)—was designed and developed based on concerted intramolecular proton-coupled electron transfer. This approach was used to develop black, magenta, yellow and blue displays as well as a multicolour bistable electrochromic shelf label. The design principles derived from this unconventional exploration of concerted intramolecular proton-coupled electron transfer may also be useful in different optoelectronic applications. Electrochromic displays that are stable in the coloured state for up to 52 h with no applied voltage are fabricated using molecules hosting concerted intramolecular proton-coupled electron transfer processes.