Chemical structures of BP1T, AC5, and AC5-CF3.
Schematic diagram of the EUPS system.
Experimental and calculated Raman spectra of (a) AC5, (b) AC5-CF3, and (c) BP1T. In (a)–(c), the upper and lower panels show the experimental and calculated spectra, respectively. The calculations are done at the B3LYP/6-31G(d) level. The peaks marked by asterisks were also observed for the substrate.
EUPS spectra of AC5-CF3, AC5, and BP1T thin films (a) before and (b) after subtracting background levels. In (b), the spectrum of AC5-CF3 is shifted by −2 eV. We relate the peaks [A]–[D] to the calculated DOS peaks. (See Sec. III B .)
Secondary spectra of AC5, BP1T, and AC5-CF3 thin films. Vertical lines show the positions of work functions determined from the spectra.
(Upper panels) EUPS spectra of (a) AC5, (b) AC5-CF3, and (c) BP1T thin films (solid curve) and calculated DOSs obtained by broadening MOs shown in the lower panels (dashed curve). (Lower panels) Energy levels of MOs calculated by the DFT method: σ, π, and F mean σ orbital, π orbital, and that mainly originated from fluorine atoms, respectively. “F orbitals” are further distinguished into those composed of F 2s and F 2p orbitals in AC5-CF3. Close and open triangles mean energy levels of the HOMO and LUMO, respectively. The energy levels of the HOMO and the LUMO are 5.16 eV and 1.70 eV in AC5, 5.51 eV and 2.11 eV in AC5-CF3, and 5.27 eV and 1.56 eV in BP1T, respectively.
Energy diagrams in AC5, AC5-CF3, and BP1T. Energy gaps between vacuum levels (E Vac) and E F are from Sec. III C . Solid line arrows are work functions. The energy levels of the HOMO and the LUMO indicated by solid lines are obtained from DFT calculation. The HOMO determined experimentally (indicated by a dashed line) is also included in AC5-CF3. 7 Dashed line arrows are optical gaps obtained from TD-DFT calculations. Dotted line arrows are from edges of photo-absorption spectra in AC5-CF3 at RT 7 and in BP1T at 10 K. 52
Functional dependence of DOSs for AC5-CF3 (Solid lines): The B3LYP, BHandHLYP, HSE06, and CAM-B3LYP functionals from the upper to lower panels. The dashed lines are the observed EUPS spectra.
Functional and basis set dependences of the HOMO and LUMO levels and the optical gaps for AC5-CF3 (eV).
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