Organic electrochromic small molecules are promising for smart windows owing to their structural tunability, diverse colors, and solution processability. However, limited near-infrared absorption, cycling stability, and modulation modes hinder their development. This presentation highlights three studies addressing stability and spectral modulation. In one study, polymer anchoring and confinement improve cycling stability, while viologen side-group design enables diverse colors^[1]. In another, polar-group interactions improve cycling reversibility, while molecular design and π-stacking regulation enhance near-infrared absorption^[2]. In the third, combining viologens with matched redox potentials and complementary absorption enables stable near-black coloration and broadband visible–near-infrared modulation. Integration with a thermochromic layer enables synergistic solar modulation^[3]. These studies provide molecular, polymer, and device design strategies for electrochromic smart windows with improved stability and spectral modulation capabilities.

Viologens,Electrochromic smart windows,Cycling stability,Broadband optical modulation