Facile fabrication of luminescent organic dots by thermolysis of citric acid in urea melt, and their use for cell staining and polyelectrolyte microcapsule labelling

• Nadezhda M. Zholobak,
• Anton L. Popov,
• Alexander B. Shcherbakov,
• Nelly R. Popova,
• Mykhailo M. Guzyk,
• Valeriy P. Antonovich,
• Alla V. Yegorova,
• Yuliya V. Scrypynets,
• Inna I. Leonenko,
• Alexander Ye. Baranchikov and
• Vladimir K. Ivanov

Beilstein J. Nanotechnol. 2016, 7, 1905–1917, doi:10.3762/bjnano.7.182

• ), making them quite toxic. In turn, nanophosphors based on rare earth elements (REE) are less harmful, but very expensive. Today, scientists are exploring the possibility of using nanoscale fluorescent carbon dots (C-dots) instead of Q-dots and REE-based nanophosphors. C-dots possess the attractive

• ]. Bourlinos et al. [24][25] heated various citrate salts, e.g., ammonium citrate in air, up to 300 °C, to produce water-soluble carbon dots of 7 nm average diameter and a fluorescence quantum yield of 3% at 495 nm excitation [24]. Doping of citric acid-based organic dots with nitrogen greatly improves their

• temperature (up to 200 °C) causes the formation of polymerized species forming amorphous carbon dots with partial sp2 hybridization. Song et al. demonstrated [39] that the primary fluorophore of a carbon dot is an independent fluorescent molecule, or possibly a molecule linked to the surface or incorporated

Facile synthesis of water-soluble carbon nano-onions under alkaline conditions

• Gaber Hashem Gaber Ahmed,
• Rosana Badía Laíño,
• Josefa Angela García Calzón and
• Marta Elena Díaz García

Beilstein J. Nanotechnol. 2016, 7, 758–766, doi:10.3762/bjnano.7.67

• , Damanhour, Egypt 10.3762/bjnano.7.67 Abstract Carbonization of tomatoes at 240 °C using 30% (w/v) NaOH as catalyst produced carbon onions (C-onions), while solely carbon dots (C-dots) were obtained at the same temperature in the absence of the catalyst. Other natural materials, such as carrots and tree

• versatile materials for chemical sensing of metal ions. The high content of lycopene in tomatoes may explain the formation of C-onions in alkaline media and a possible formation mechanism for such structures was outlined. Keywords: carbon dots; carbon onions; metal-ion sensing; photoluminescence; thermal

• sensors. The more popular and extensively investigated carbon-based nanomaterials include carbon dots (C-dots), fullerenes, nanotubes and graphene, while others, such as nanodiamonds and carbon onions, stayed forgotten for a long time, in spite of the fact that these carbon nanoparticles (C-NPs) were

Nanostructure sensitization of transition metal oxides for visible-light photocatalysis

• Hongjun Chen and
• Lianzhou Wang

Beilstein J. Nanotechnol. 2014, 5, 696–710, doi:10.3762/bjnano.5.82

• for more detailed information [106]. Carbon nanodots are a new class of carbon nanomaterials and consist of discrete, quasipherical nanoparticles with sizes below 10 nm [107][108][109][110]. Since they have been reported on in 2004 for the first time [111], carbon dots have gradually become an

• important member in the nanocarbon family due to their benign, abundant and low-cost nature. As carbonaceous quantum dots, carbon nanodots display PL behavior dependent on their size and the excitation wavelength. In addition, carbon dots are also characterized by water solubility, chemical inertness and