Chemically Switchable Ultraviolet Luminescence (IMAGE) Drexel University Caption In the presence of a water molecule on its surface, lanthanum aluminate film on a strontium titanate crystal emits ultraviolet light from its interior. (Illustration not to scale). Credit Drexel University Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.