Molecules Display Optical Switching

In the April 9 issue of Science, a team from the University of Groningen and from Syncom, both in Groningen, the Netherlands, has described a self-assembling molecular system that exhibits novel optically switchable behavior. The group suggests that the material points to potential applications of similar systems in molecular memory and smart materials.

Based on a dithienylethene photochromic unit functionalized with amide groups, the substance changes shape upon exposure to 313-nm radiation, giving it different electronic and viscoelastic properties. In the experiments, the researchers dissolved the substance in toluene. They discovered that they could cycle it among four states by applying a combination of UV radiation or 460-nm light and heating or cooling.