Excitation-Independent Emission of Carbon Quantum Dot Solids

• Main Authors: Xuan-Dung Mai, Yen Thi Hai Phan, Van-Quang Nguyen
• Format: Article
• Language: English
• Published: Hindawi Limited 2020-01-01
• Series: Advances in Materials Science and Engineering
• Online Access: http://dx.doi.org/10.1155/2020/9643168

Solid assemblies of carbon quantum dots (CQDs) are important for diverse applications including LEDs, solar cells, and photosensors; their optical and electrical properties have not been explored yet. Herein, we used amphiphilic CQDs synthesized from citric acid and thiourea by a solvothermal method to fabricate CQD solid films. Optical properties of CQDs studied by UV-Vis and photoluminescence spectroscopies indicate that CQDs possess three different emission centers at 425 nm, 525 nm, and 625 nm originating from C sp2 states, N-states, and S-states, respectively. In a solid state, π-π stacking quenched the blue emission, while the red emission increased. Importantly, CQD films exhibited excitation independence, which is important to design solid-state lighting applications.