% IMPORTANT: The following is UTF-8 encoded.  This means that in the presence
% of non-ASCII characters, it will not work with BibTeX 0.99 or older.
% Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or
% “biber”.

@ARTICLE{Meierhofer:893896,
      author       = {Meierhofer, Florian and Weigert, Florian and Dissinger,
                      Frank and Jungclaus, Jörgen and Müller-Caspary, Knut and
                      Waldvogel, Siegfried R. and Resch-Genger, Ute and Voss,
                      Tobias},
      title        = {{C}itric {A}cid {B}ased {C}arbon {D}ots with {A}mine {T}ype
                      {S}tabilizers: p{H}-{S}pecific {L}uminescence and {Q}uantum
                      {Y}ield {C}haracteristics},
      journal      = {The journal of physical chemistry / C},
      volume       = {124},
      number       = {16},
      issn         = {1932-7455},
      address      = {Washington, DC},
      publisher    = {Soc.},
      reportid     = {FZJ-2021-02908},
      pages        = {8894 - 8904},
      year         = {2020},
      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.},
      cin          = {ER-C-1},
      ddc          = {530},
      cid          = {I:(DE-Juel1)ER-C-1-20170209},
      pnm          = {5351 - Platform for Correlative, In Situ and Operando
                      Characterization (POF4-535) / moreSTEM - Momentum-resolved
                      Scanning Transmission Electron Microscopy (VH-NG-1317)},
      pid          = {G:(DE-HGF)POF4-5351 / G:(DE-HGF)VH-NG-1317},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000529225800047},
      doi          = {10.1021/acs.jpcc.9b11732},
      url          = {https://juser.fz-juelich.de/record/893896},
}