Density of the unoccupied electronic states of the ultrathin films of the aziridinylphenylpyrrol substituted fullerene

作者：Komolov A S; Lazneva E F; Gerasimova N B; Panina Yu A; Zashikhin G D; Baramygin A V; Si P; Akhremtchik S N; Gavrikov A A

来源：Journal of Electron Spectroscopy and Related Phenomena, 2015, 205: 52-56.

DOI：10.1016/j.elspec.2015.08.002

• Electron-solid scattering and transmission - elastic
• DFT calculations
• Ultrathin organic semiconducting films
• Density of states
• Substituted fullerene

The ultrathin films of aziridinylphenylpyrrol-C-50 (APP-C-60) and of the unsubstituted C-60 thermally deposited in UHV on an oxidized silicon substrate (SiO2)n-Si were studied experimentally using the very low energy electron diffraction (VLEED) method and the total current spectroscopy (TCS) measurement scheme. The density of the unoccupied electronic states (DOUS) located 2-20 eV above the Fermi level (E-F) of the films under study was determined using the TCS results and using the results of the density functional theory (DFT) calculations of the vacant electronic orbitals of the APP-C-60 and C-60 molecules. The DOUS peak structure obtained on the basis of the calculation results corresponds well to the structure of the major DOUS bands obtained from the TCS experiment. The comparison of the DOUS spectra of the APP-C-60 and C-60 films under study showed that the introduction of the APP substituent to the C-60 molecule was accompanied by the pronounced changes of the pi* DOUS bands in the energy range from 2 eV to 5 eV above E-F and of the DOUS band composed from both pi* and sigma* - type orbitals in the energy range from 5 eV to 9 eV above E-F. The formation of the low-lying sigma* DOUS band in the APP-C-60 film in the energy range from 8 eV to 13 eV above E-F can be explained by the superposition of the relevant DUDS maxima from the C-60 film and from the APP fragment.

• 出版日期2015-11
• 单位山东大学