A Bifunctional Electrochromic/Electrofluorochromic Ionic Liquid Enables Displayable Smart Windows with High Energy Efficiency

The integration of display functionality into electrochromic (EC) smart windows offers a promising avenue for enhancing energy efficiency, urban aesthetics, and public interaction in modern high-rise buildings. However, their development has been impeded by the limited choice of electroactive materials with effective solar spectral modulation, high optical contrast, and visible fluorescence. In this study, a bifunctional electrochromic/electrofluorochromic (EC/EFC) ionic liquid containing triphenylamine, carbazole, and imidazole moieties (EEIL) is designed and synthesized. Displayable smart windows are constructed using a pixel confinement strategy and exhibits impressive programmed reflective/emissive dual-modal display performance with high optical contrast across diverse lighting environments. Notably, the device exhibits exceptional optical/thermal management characteristics within the solar radiation spectrum range, achieving an energy efficiency of 13.44% of the total energy consumption. The synergistic integration of dual-modal display capabilities with efficient optical and thermal management has contributed to the development of sustainable and interactive urban environments.