| Autor: |
Timofeeva, Tamara E., Egorova, Marfa N., Tomskaya, Aleksandra E., Grigor'ev, Yuri M., Popov, Sergey V., Sharin, Egor P. |
| Předmět: |
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| Zdroj: |
AIP Conference Proceedings; 2020, Vol. 2328 Issue 1, p1-4, 4p |
| Abstrakt: |
We report on results of first-principles density-functional theory (DFT) calculations of energy levels of molecular orbitals (MO) and results of electronic excitation spectra calculations performed using Tamm-Dancoff approximation (TDA) to time- dependent density functional theory (TDDFT) of graphene quantum dots (GQDs) with edge functionalization. Polyciclic aromatic hydrocarbon models of GQDs functionalized with oxide and amine groups -OH, -COOH, -COH, NH2 were considered. The calculation results showed that with an increase in the diameter of the GQDs ELUMO-EHOMO decreases, the oxide groups -COOH, -COH shift these levels lower relative to the energy levels of the GQDs passivated by the -H atom due to the withdrawal of electrons from the graphene skeleton. The calculated electronic excitation spectra were compared with the UV- Vis spectra of hydrothermally synthesized carbon quantum dots. Comparison of the calculation results and experimental spectra shows a qualitative agreement, which make it is possible to suggest that the considered disk-shaped models of GQDs (coronene and C54H18 molecules) can be basic absorbing structures of the GQDs or carbon quantum dots. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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