Electronic excited states of a strongly correlated organic radical 1,3,5-trithia-2,4,6-triazapentalenyl (TTTA) adsorbed on a Si(001) surface

• Published in: Physical chemistry chemical physics : PCCP 2013-01, Vol.15 (44), p.19213-1922
• Main Authors: Shudo, K, Satake, T, Shimatsu, T, Uchiyama, M, Takeda, J
• Format: Article
• Language: English
• Subjects: Chemistry; Correlation; Covalent bonds; Density; Electronics; Exact sciences and technology; Excitation spectra; General and physical chemistry; Radicals; Semiconductors; Spectra
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/c3cp52919c

Electronic excited states of a strongly correlated organic radical, 1,3,5-trithia-2,4,6-triazapentalenyl (TTTA), adsorbed on a Si(001) surface were investigated by means of two-photon photoemission spectroscopy (2PPE) to elucidate the functional organic thin-film formation on a typical semiconductor substrate. The spectra were interpreted with the aid of density functional theoretical calculations. The unpaired electron of TTTA forms a covalent bond with the dangling bond of the Si-dimer initially, and there are resonant states of TTTA to Si near the surface. The molecules adsorbed at room temperature form dimers having diamagnetic properties at thicknesses of a few monolayers, while the paramagnetic phase appears at multilayer thickness. From the change in the work function, the orientation of the adsorbed TTTA molecules was determined to change depending on the thickness of the adsorbed layer. Electronic excited states of a 1,3,5-trithia-2,4,6-triazapentalenyl (TTTA, a functional radical) adsorbed on a typical semiconductor surface were investigated by means of two-photon photoemission spectroscopy (2PPE) to elucidate organic thin-film formation.