1
|
Zhang B, Wang B, Ushakova EV, He B, Xing G, Tang Z, Rogach AL, Qu S. Assignment of Core and Surface States in Multicolor-Emissive Carbon Dots. Small 2022:e2204158. [PMID: 36216592 DOI: 10.1002/smll.202204158] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 09/16/2022] [Indexed: 06/16/2023]
Abstract
It is important to reveal the luminescence mechanisms of carbon dots (CDs). Herein, CDs with two types of optical centers are synthesized from citric acid in formamide by a solvothermal method, and show high photoluminescence quantum yield reaching 42%. Their green/yellow emission exhibits pronounced vibrational structure and high resistance toward photobleaching, while broad red photoluminescence is sensitive to solvents, temperature, and UV-IR. Under UV-IR, the red emission is gradually bleached due to the photoinduced dehydration of the deprotonated surface of CDs in dimethyl sulfoxide, while this process is hindered in water. From the analysis of steady-state and time-resolved photoluminescence and transient absorption data together with density functional theory calculations, the green/ yellow emission is assigned to conjugated sp2 -domains (core state) similar to organic dye derivatives stacked within disk-shaped CDs; and the broad red emission-to oxygen-containing groups bound to sp2 -domains (surface state), whereas energy transfer from the core to the surface state can happen.
Collapse
Affiliation(s)
- Bohan Zhang
- Joint Key Laboratory of the Ministry of Education, Institute of Applied Physics and Materials Engineering, University of Macau, Taipa, Macau SAR, 999078, P. R. China
| | - Bingzhe Wang
- Joint Key Laboratory of the Ministry of Education, Institute of Applied Physics and Materials Engineering, University of Macau, Taipa, Macau SAR, 999078, P. R. China
| | - Elena V Ushakova
- Center of Information Optical Technologies, ITMO University, Saint Petersburg, 197101, Russia
| | - Bingchen He
- Joint Key Laboratory of the Ministry of Education, Institute of Applied Physics and Materials Engineering, University of Macau, Taipa, Macau SAR, 999078, P. R. China
| | - Guichuan Xing
- Joint Key Laboratory of the Ministry of Education, Institute of Applied Physics and Materials Engineering, University of Macau, Taipa, Macau SAR, 999078, P. R. China
| | - Zikang Tang
- Joint Key Laboratory of the Ministry of Education, Institute of Applied Physics and Materials Engineering, University of Macau, Taipa, Macau SAR, 999078, P. R. China
| | - Andrey L Rogach
- Department of Materials Science and Engineering, and Centre for Functional Photonics (CFP), City University of Hong Kong, Kowloon, Hong Kong SAR, 999077, P. R. China
- Shenzhen Research Institute, City University of Hong Kong, Shenzhen, 518057, P. R. China
| | - Songnan Qu
- Joint Key Laboratory of the Ministry of Education, Institute of Applied Physics and Materials Engineering, University of Macau, Taipa, Macau SAR, 999078, P. R. China
- Department of Physics and Chemistry, Faculty of Science and Technology, University of Macau, Macao SAR, 999078, P. R. China
| |
Collapse
|