[11p-W621-1~18] 17.1 Carbon nanotubes & other nanocarbon materials

[11p-W621-1] Geometric and electronic structures of two-dimensionally polymerized triptycene

〇(M1)Yasumaru Fujii¹, Mina Maruyama¹, Susumu Okada¹ (1.Univ. of Tsukuba)

Keywords:hydrocarbon, polymer

On the basis of the density functional theory with generalized gradient approximation, we investigated the geometric and electronic structures of two-dimensional covalent networks consisting of triptycene and phenyl groups, which are alternately arranged hexagonally. Calculated total energies of the networks are 48-63 meV per atom higher than that of an isolated benzene, indicating that the networks are energetically stable. All networks were semiconductors with a moderate band gap at the Γ point, the value of which is inversely proportional to the length of polyphenyl connecting triptycene. According to a kagome topology of π electrons distributed on sp² hydrocarbons, the characteristic kagome energy bands consisting of a flat dispersion band and a Dirac cone emerge in valence and conduction states whose structure is sensitive to the mutual orientation of phenyl groups with respect to the polymer chain.