OSAKA UNIVERSITY researchers have discovered a novel material that transitions from a crystal to a liquid and exhibits changes in luminescence when irradiated with UV light, enabling a molecular-level visualisation of the crystal-melting process. The finding is unprecedented as the melting is induced by light alone. More intriguing, it changes colour as it melts. The work was published in Chemical Science. This new class of photo-responsive crystal compounds are called “heteroaromatic 1,2-diketones” and the phenomenon photo-induced crystal-to-liquid transition (PCLT).
The colour changes indicate that the material underwent molecular-level changes in shape, which caused variations in light absorption and emission. The work provides insights into the mechanism of crystal melting and will enable greater opportunities for the design of PCLT materials with a variety of applications.