Synthesis of Single-Crystalline Hexagonal Graphene Quantum Dots from Solution Chemistry

• Published in: Nano letters Vol. 19; no. 8; pp. 5437 - 5442
• Main Authors: Lee, Seok Hwan, Kim, Do Youb, Lee, Jaemin, Lee, Seul Bee, Han, Hyun, Kim, Young Yun, Mun, Sung Cik, Im, Sang Hyuk, Kim, Tae-Ho, Park, O Ok
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 14-08-2019
• Subjects: deep-blue electroluminescence; single-crystalline; bottom-up synthesis; hexagonal structure; Graphene quantum dots
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/acs.nanolett.9b01940

Graphene-based carbon nanostructures with nanometer dimensions have been of great interest due to the existence of a bandgap. So far, well-ordered edge structure and uniformly synthesized graphene quantum dots (GQDs) with a hexagonal single-crystalline structure have not been directly observed owing to the limited precision of current synthesis approaches. Herein, we report on a novel approach not just for the synthesis of the size-controlled single-crystalline GQDs with hexagonal shape but also for a new discovery on constructing 2D and 3D graphene single crystal structures from d-glucose via catalytic solution chemistry. With size-controlled single-crystalline GQDs, we elucidated the crucial role of edge states on luminescence from the correlation between their crystalline size and exciton lifetime. Furthermore, blue-emissive single-crystalline GQDs were used as an emitter on light-emitting diodes and exhibit stable deep-blue emission regardless of the voltage and doping level.