Probing Energy and Electron Transfer Mechanisms in Fluorescence Quenching of Biomass Carbon Quantum Dots.
The recent discovery of biomass-derived carbon quantum dots (CQDs) offers the potential to extend the sensing and imaging capabilities of quantum dots (QDs) to applications that require biocompatibility and environmental friendliness. Many studies have confirmed the exciting optical properties of CQDs and suggested a range of applications, but realizing the potential of CQDs will require a deeper fundamental understanding of their photophysical behavior. Here, biomass-derived CQDs were synthesized by hydrothermal processing methods from the aminopolysaccharide chitosan, and their fluorescence quenching behaviors were investigated. A family of nitroaromatics with different ring substituents was used to generate systematically varying CQD-quenching behaviors. Experimental evidence including a correlation between quenching constant and spectral overlap, fluorescence lifetime decay, and donor-acceptor distance all demonstrate that the primary mechanism for QCD-quenching is Förster resonance energy transfer (FRET) and not electron transfer. Spectroelectrochemical studies with redox-dependent quenching molecules and studies with complex dye molecules further support this conclusion. We envision this fundamental understanding of CQDs will facilitate the application of these emerging nanomaterials for sensing and imaging.
State Key Laboratory of Pulp and Papermaking Engineering, South China University of Technology , Guangzhou, 510640, P. R. China.
Zicheng
Z
Liang
Fischell Department of Bioengineering and Institute for Bioscience and Biotechnology Research, University of Maryland , College Park, Maryland 20742, United States.
Mijeong
M
Kang
Fischell Department of Bioengineering and Institute for Bioscience and Biotechnology Research, University of Maryland , College Park, Maryland 20742, United States.
Gregory F
GF
Payne
State Key Laboratory of Pulp and Papermaking Engineering, South China University of Technology , Guangzhou, 510640, P. R. China.
Xiaohui
X
Wang
State Key Laboratory of Pulp and Papermaking Engineering, South China University of Technology , Guangzhou, 510640, P. R. China.|Institute of Biomass Chemistry and Technology, Beijing Forestry University , Beijing 100083, P. R. China.
Runcang
R
Sun
Förster resonance energy transfer; carbon quantum dot; chitosan; fluorescence quenching; spectroelectrochemistry