A research group from the Keio University Graduate School of Science and Technology including Ph.D. student Shuichiro Hayashi, Master student Kaneto Tsunemitsu, and Associate Professor Mitsuhiro Terakawa have revealed that fluorescent Graphene Quantum Dots (GQDs) are synthesized by irradiation of laser pulses onto transparent polymers.
Quantum dots are nano-sized particles that exhibit photoluminescence owing to quantum confinement effects, and are suitable for applications such as light-emitting diodes, biomarkers, and anticounterfeiting security tags. Particularly, GQDs have attracted significant attention as an eco-friendly alternative to conventional QDs in the context of sustainable development. In this work, it has been revealed that by irradiating and scanning focused ultrashort laser pulses, GQDs can be simultaneously synthesized and patterned along desired paths, similar to drawing with a pen. Since the presented method is based on multiphoton interactions, GQDs can be patterned, not just two-dimensionally on the surface, but three-dimensionally inside of the transparent polymer substrate. This work expands the possibilities of GQDs for applications in novel flexible optoelectrical devices.
This work was published in Nano Letters on December 28, 2021 (EST)