| Affiliation: | 1. College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing, 100875 China These authors contributed equally to this work.;2. State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023 China;3. College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing, 100875 China;4. Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029 China |
| Abstract: | Carbon quantum dots (CQDs) feature bright and tunable photoluminescence, solution processability, and low toxicity, showing great potential in optoelectronics. However, the large-scale synthesis of CQDs with near-unity photoluminescence quantum yield (PLQY) has not been achieved so far. In this study, we perform radical-assisted synthesis of hexagon-shaped CQDs (H-CQDs) delivering near-unity PLQY (96 %). Experimental and theoretical analyses revealed that the large vertically oriented transition dipole moment of H-CQDs originating from high symmetry results in nearly 100 % PLQY. The H-CQDs also exhibited a high electron mobility of up to 0.07 cm2 V−1 s−1. These properties enable the H-CQD-based light-emitting diodes with a high external quantum efficiency of 4.6 % and a record maximum brightness of over 11 000 cd m−2. This study represents a significant advance that CQDs-based electroluminescent device can be utilized for potential display and lighting applications. |
