In a study published in Nature Communications, an international team led by Aalto University researchers has found that fibrous red phosphorous, when electrons are confined in its one-dimensional sub-units, can show large optical responses – that is, the material shows strong photoluminescence under light irradiation. Red phosphorous, like graphene, belongs to a unique group of materials discovered in 2017 called one-dimensional van der Waals (1D vdW) materials.