Researchers at Durham University have identified unusual light-emitting properties in two carbon-based molecules, with findings that could inform the development of future photonic materials.

The two studies, published in Nature Communications, investigate how molecular structure influences the absorption and emission of light.

The first focuses on monohomotruxene (MHTX), a molecule made entirely from carbon and hydrogen. Researchers found that it produces a cyan-blue phosphorescent glow lasting more than 12 seconds after the excitation source is switched off, even at room temperature.

The finding is notable because the molecule produces persistent phosphorescence without relying on heavy metals, which are used in some existing light-emitting materials. Potential applications could include security printing, anti-counterfeiting technologies and quantum technologies.

The second study examines HzTFEX2, providing experimental evidence for an unusual arrangement of molecular energy levels that had previously been predicted theoretically. The effect was observed under carefully controlled, low-temperature conditions.

Led by PhD student Carolina Francener and Professor Andrew Monkman from Durham's Department of Physics, the research involved collaborators in Brazil, France and Japan.

Monkman said the studies had revealed unexpected photophysical properties in relatively simple organic molecules, potentially opening up new opportunities in photonics.

Further research will be needed to establish how the findings might translate into practical materials and devices.