Olla Chiara, Porcu Stefania, Secci Francesco, Ricci Pier Carlo, Carbonaro Carlo Maria
Department of Physics, University of Cagliari, Cittadella Universitaria, I-09042 Monserrato, Italy.
Department of Chemistry and Geological Science, University of Cagliari, Cittadella Universitaria, I-09042 Monserrato, Italy.
Materials (Basel). 2022 Feb 16;15(4):1468. doi: 10.3390/ma15041468.
The introduction of N doping atoms in the carbon network of Carbon Dots is known to increase their quantum yield and broaden the emission spectrum, depending on the kind of N bonding introduced. N doping is usually achieved by exploiting amine molecules in the synthesis. In this work, we studied the possibility of introducing a N-N bonding in the carbon network by means of hydrothermal synthesis of citric acid and hydrazine molecules, including hydrated hydrazine, di-methylhydrazine and phenylhydrazine. The experimental optical features show the typical fingerprints of Carbon Dots formation, such as nanometric size, excitation dependent emission, non-single exponential decay of photoluminescence and G and D vibrational bands in the Raman spectra. To explain the reported data, we performed a detailed computational investigation of the possible products of the synthesis, comparing the simulated absorbance spectra with the experimental optical excitation pattern. The computed Raman spectra corroborate the hypothesis of the formation of pyridinone derivatives, among which the formation of small polymeric chains allowed the broad excitation spectra to be experimentally observed.
已知在碳点的碳网络中引入氮掺杂原子会提高其量子产率并拓宽发射光谱，这取决于引入的氮键类型。氮掺杂通常通过在合成过程中利用胺分子来实现。在这项工作中，我们研究了通过柠檬酸和肼分子（包括水合肼、二甲基肼和苯肼）的水热合成在碳网络中引入N-N键的可能性。实验光学特征显示了碳点形成的典型特征，如纳米尺寸、激发依赖发射、光致发光的非单指数衰减以及拉曼光谱中的G和D振动带。为了解释所报道的数据，我们对合成的可能产物进行了详细的计算研究，将模拟吸收光谱与实验光学激发模式进行了比较。计算得到的拉曼光谱证实了吡啶酮衍生物形成的假设，其中小聚合物链的形成使得在实验中观察到了宽激发光谱。
