The Advanced Coating Technology Research Center of National Institute of Advanced Industrial Science and Technology (AIST) and Tateyama Kagaku Industry Co Ltd (Toyama City, Toyama Prefecture) developed a luminous material supporting LED lamps.
Also, they developed a high-brightness luminous sheet by coating a plastic substrate (e.g. polyethylene terephthalate (PET) substrate) with the luminous material. The new material is targeted at the evacuation routes of skyscrapers, etc.
Luminous materials available in the market usually store light by absorbing ultraviolet light. However, indoor fluorescent lamps are being replaced with LED lamps, whose light does not contain ultraviolet light, to save energy, reducing afterglow luminance and time.
This time, AIST and Tateyama Kagaku used a metal organic compound-based "chemical solution method" to develop a new luminous material into which metal ions are injected and developed a process to synthesize the material.
When LED light with a wavelength of 460nm is applied to the new material, it glows because electrons in the material are excited, and it continues to glow even after the excitation. While the brightness of a commercially-available luminous material decreased to 10mcd/m2 (light that can be very clearly recognized in a dark place) two hours after stopping the excitation by LED, the brightness of the new material was 10mcd/m2 four hours after the excitation.
Also, the brightness of the new material 10 minutes after the excitation was 602mcd/m2, which was about three times higher than that of the commercially-available material.