Add energy to phase-change materials such as phosphors, and they glow in the dark. The challenge for scientists has been to produce long-lasting phosphorescence in specific hues. Now, the University of Georgia Research Foundation Inc., Athens, Ga., and the University of Puerto Rico, Mayagüez, Puerto Rico, have illuminated the field with a patented portfolio of seven phosphors that can be mixed to provide tints and hues that glow for up to 24 hours.
The UGARF/UPR technology is environmentally safe, containing no sulfur, radioactive materials, lead or other hazardous substances. An international, non-exclusive license for the UGARF/UPR phosphors was granted to Performance Indicator LLC, Lowell, Mass., a company focused on indicator chemicals for military and anti-counterfeiting use. Using an inorganic, nontoxic and highly efficient material in the presence of any light source with a UV component, the photoluminescent material will absorb and slowly release light. The technology can create a broad palette of daytime colors, and the same or different nighttime emissive colors, providing high intensity and long duration glow. Other potential consumer and industrial applications include signage, paints, color-coded electrical wiring, textiles and printing ink. The phosphors can be mixed with polymers or resins without substantially changing the matrix.