Organics glow longer without depending on rare metals
Summary
Applying a new strategy for combining carbon-based organic molecules, researchers at Kyushu University and the Okinawa Institute of Science and Technology (OIST) have dramatically improved the length and strength of the glow produced by the versatile materials, which have the potential to be more easily formed into paints and fibers than their rare-metal-containing counterparts. Formally known as persistent luminescence, the glow-in-the-dark phenomenon is also often referred to as phosphorescence, though this term leads to ambiguity with another emission mechanism commonly found in organic materials. “By changing our design strategy, we have now succeeded in improving the performance of organic persistent luminescence by about ten times over our previous report,” said Ryota Kabe, Assistant Professor and Leader of the Research at OIST with Zesen Lin. Holes are generally more stable and less reactive with oxygen, so the light emission was much longer in air than with their previous materials in which the excited electrons were mobile. Additionally, the researchers were able to further stabilise the energy storage state by adding a third organic material that essentially traps the holes to further delay their return and extend the emission duration.