Journal Article

FZJ-2021-02908

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Citric Acid Based Carbon Dots with Amine Type Stabilizers: pH-Specific Luminescence and Quantum Yield Characteristics

Meierhofer, F. ; Weigert, F. ; Dissinger, F. ; Jungclaus, J. ; Müller-Caspary, K.FZJ* ; Waldvogel, S. R.Extern* ; Resch-Genger, U. (Corresponding author)Extern* ; Voss, T. (Corresponding author)Extern*

2020
Soc. Washington, DC

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Please use a persistent id in citations: http://hdl.handle.net/2128/28123  doi:10.1021/acs.jpcc.9b11732

Abstract: We report the synthesis and spectroscopic characteristics of two different sets of carbon dots (CDs) formed by hydrothermal reaction between citric acid and polyethylenimine (PEI) or 2,3-diaminopyridine (DAP). Although the formation of amide-based species and the presence of citrazinic acid type derivates assumed to be responsible for a blue emission is confirmed for both CDs by elemental analysis, infrared spectroscopy, and mass spectrometry, a higher abundance of sp2-hybridized nitrogen is observed for DAP-based CDs, which causes a red-shift of the n-π* absorption band relative to the one of PEI-based CDs. These CD systems possess high photoluminescence quantum yields (QY) of ∼40% and ∼48% at neutral pH, demonstrating a possible tuning of the optical properties by the amine precursor. pH-Dependent spectroscopic studies revealed a drop in QY to < 9% (pH ∼ 1) and < 21% (pH ∼ 12) for both types of CDs under acidic and basic conditions. In contrast, significant differences in the pH-dependency of the n-π* transitions are found for both CD types which are ascribed to different (de)protonation sequences of the CD-specific fluorophores and functional groups using zeta potential analysis.

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Contributing Institute(s):

1. Physik Nanoskaliger Systeme (ER-C-1)

Research Program(s):

1. 5351 - Platform for Correlative, In Situ and Operando Characterization (POF4-535) (POF4-535)
2. moreSTEM - Momentum-resolved Scanning Transmission Electron Microscopy (VH-NG-1317) (VH-NG-1317)

Appears in the scientific report 2021

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Database coverage:
; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; Essential Science Indicators ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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