A solvent-governed surface state strategy for rational synthesis of N and S co-doped carbon dots with multicolour fluorescence

ABSTRACT

Multicolour emissive carbon dots (CDs) are widely investigated by virtue of their merits on fluorescent properties. Method on heteroatom doping assisted with various solvents has been proved efficient in achieving multiple-colour-emissive CDs, especially long-wavelength emission. Herein, a synthesis of multicolour-emissive CDs by controlled surface function is reported. By tuning the thermal-pyrolysis temperature and molar ratio of reactants, optimal emission of the resulted CDs gradually shifts from blue to yellow light with the assistance of different solvents. According to the emissive relationship dependent on excitation, fluorescence lifetimes, and FT-IR of these CDs, the different surface states participated with S and N elements on the surface of carbogenic core govern fluorescent colours of the CDs. In terms of the applications, blue CDs (B-CDs) exhibits high sensitivity for ion detections of Ag⁺ and Fe³⁺, which is further illustrated to have different quenching mechanisms each other because that these ions have the affinity interaction with different surface groups of the CDs. Moreover, blue and yellow CDs solutions are mixed with PVP water solution to fabricate white-light CDs/PVP film, which exhibits stable fluorescence with a CIE coordinate of (0.32, 0.33) and endows these CDs as potentially fluorescent nanomaterial in the solid state lighting field.

GRAPHICAL ABSTRACT

KEYWORDS:

• S,N-codoped CDs
• multicolour emission
• surface state
• ion detection
• white-light film

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Zhenxing Qin http://orcid.org/0000-0003-1164-6547

Yi Zhou http://orcid.org/0000-0002-7220-0568

Additional information

Funding

This work in China was supported by the Key R & D Projects of Shanxi Province [201903D321111], the National Natural Science Foundation of China [51502189, 51871158, 11705124, 11704274, and 11772177], the Foundation of the Outstanding Young Scholars of Shanxi Province [201801D211006], the Applied Basic Research Project of Shanxi Province [201801D121084 and 201801D221121], the Natural Science Foundation of Shanxi Province [201701D221001], the Fund for Shanxi ‘1331 Project’ Key Innovative Research Team [1331KIRT], Shanxi Graduate Education Innovation Project [2019SY501], the Jinzhong Science and Technology Innovation Carrier and Platform Construction Project [P182002], and the School-enterprise Technology Development Cooperation Project [201940].