Mohammad-Jafarieh Parisa, Akbarzadeh Abolfazl, Salamat-Ahangari Rahman, Pourhassan-Moghaddam Mohammad, Jamshidi-Ghaleh Kazem
Department of Chemistry, Faculty of Basic Sciences, Azarbaijan Shahid Madani University, 35 km Tabriz-Maraghe Road, P. O. Box 53714161, Tabriz, Iran.
Department of Medical Biotechnology, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran.
BMC Chem. 2021 Sep 25;15(1):53. doi: 10.1186/s13065-021-00779-6.
Carbon dots (C-dots) are photoluminescent nanoparticles with less than 10 nm in size. Today, many studies are performed to exploit the photoluminescence (PL) property of carbon dots, and our focus in this study is to estimate the dipole moment of carbon dots. For reaching our aims, C-dots were synthesized and dissolved in the different solvents.
Carbon dots with intense photoluminescence properties have been synthesized by a one-step hydrothermal method from a carbon bio-source. In this research, we report on the effect of aprotic solvents on absorption and fluorescence spectra and dipole moments of C-dots dispersed in a range of many aprotic solvents with various polarity and dielectric constant at room temperature. The change in the value of dipole moment was estimated by using the Stokes shifts. The difference between the dipole moment of the excited state and the ground state was shown using an extended form of Lippert equations by Kawski and co-workers.
The values found for μ = 1.077 D, and μ = 3.157 D, as well as the change in the dipole moments. The results showed that the dipole moment of the excited state is more than the ground state, indicating a high density and redistribution of electrons in the excited state. Finally, the quantum yield of C-dots in the eclectic aprotic solvents was communicated and discussed.
碳点（C点）是尺寸小于10纳米的光致发光纳米颗粒。如今，人们开展了许多研究来探索碳点的光致发光（PL）特性，而本研究的重点是估算碳点的偶极矩。为实现我们的目标，合成了碳点并将其溶解于不同溶剂中。
通过一步水热法从碳生物源合成了具有强烈光致发光特性的碳点。在本研究中，我们报告了在室温下，非质子溶剂对分散于一系列具有不同极性和介电常数的多种非质子溶剂中的碳点的吸收光谱、荧光光谱和偶极矩的影响。通过斯托克斯位移估算偶极矩值的变化。使用Kawski及其同事提出的扩展形式的Lippert方程展示了激发态和基态偶极矩之间的差异。
得到了μ = 1.077 D和μ = 3.157 D的值以及偶极矩的变化。结果表明，激发态的偶极矩大于基态，这表明激发态中电子的高密度和重新分布。最后，交流并讨论了碳点在混合非质子溶剂中的量子产率。
