An organic, glow-in-the-dark material that can emit light for over an hour is reported in a study in Nature this week. Compared to systems currently in use for the production of glow-in-the-dark materials, the material demonstrated does not contain rare elements or require high fabrication temperatures.

Long persistent luminescence (LPL) materials are used widely as glow-in-the-dark paints for watches and emergency signs. However, the inorganic system that forms the basis of most commercial glow-in-the-dark paints requires not only rare elements for long-lived emission, but also temperatures of over 1,000 degrees Celsius in the fabrication process. Until now, extended light emission from organic molecules (known as phosphorescence), has lasted for only a few minutes.

Ryota Kabe and Chihaya Adachi demonstrate the production of organic LPL for over one hour at room temperature using two simple organic molecules. Compared to the present inorganic LPL systems, the organic LPL system presented here is free of rare elements, transparent and easier to fabricate and process. The authors suggest that this system has the potential to be flexible and colour tuneable with further development. The authors hope that these properties will enable applications for LPL in fabrics, windows, paints and imaging in living organisms.