Blue Films; August 1993; Scientific American Magazine; by W. Wayt Gibbs; 2 Page(s)
One summer's day at Princeton University in 1991 a funny thing happened on the way to Guyot Hall. As Lori A. Vermeulen, a doctoral student in chemistry, carried samples of an organic/inorganic composite across campus, the white powdery material turned blue. "This was surprising," Vermeulen recalls. "When these compounds decompose, they turn yellow, brown, red--but they don't turn blue."
Back in the laboratory Vermeulen and assistant professor Mark E. Thompson got another surprise. They found that the material, zirconium phosphonate viologen chloride (ZPVC), changed color not because it was decomposing but because it was absorbing--and storing--ultraviolet light energy.