Battery-independent emergency illumination with RGB phosphors

Acrylic resins that emit red, green, or blue (RGB) phosphorescence were fabricated. Mixtures of an organic dye and green phosphor created bright afterglow emission in the spectral region from yellow to red, which were difficult to attain with conventional red phosphors. Rhodamine and kiton were suitable for converting green phosphorescence to orange or red fluorescence. The resins continued to glow in darkness for longer than 3 h after an excitation lamp had been turned off. This long-afterglow characteristic of the current dye/phosphor mixtures was in a remarkable contrast with the fast phosphorescence decay of the conventional red phosphors (10-20 min). These red afterglow resins improve visibility of emergency signs, and realize warm-colored illumination that provides a sense of security in darkness.