Near-infrared absorption of π-stacking columns composed of trioxotriangulene neutral radicals

Yasuhiro Ikabata, Qi Wang, Takeshi Yoshikawa, Akira Ueda, Tsuyoshi Murata, Kazuki Kariyazono, Miki Moriguchi, Hiroshi Okamoto, Yasushi Morita*, Hiromi Nakai


研究成果: Article査読

18 被引用数 (Scopus)


A long-wavelength photoabsorption of organic molecules has been noticed because of the potential as materials. In addition to the extension of π conjugation, molecular aggregation has been utilized to realize the elongation of absorption wavelength. We report strong near-infrared absorptions of trioxotriangulene neutral radicals in the crystalline state and large-scale theoretical calculations of the radical assemblies interpreting the mechanism of optical properties. Polarized absorption spectra and X-ray diffraction of the crystals clarified that an unusual π-stacking column consisting of π-dimers is key for this absorption. Quantum chemical calculations based on time-dependent density functional theory revealed that the π-dimer shows an electronic transition between frontier orbitals generated by strong coupling of the delocalized singly occupied orbitals of monomers. The interdimer interaction of transition dipole moments, which are parallel to the column, elucidated the increase of absorption wavelength. The divide-and-conquer Green function method enabled the large-scale time-dependent density functional theory calculation up to a 60mer, where the maximum number of atoms is 4380, reproducing the near-infrared absorptions of trioxotriangulene crystals. The present method to investigate the mechanism of the long-wavelength photoabsorption is useful for developing organic materials consisting of stable neutral radicals.

ジャーナルnpj Quantum Materials
出版ステータスPublished - 2017 12月 1

ASJC Scopus subject areas

  • 電子材料、光学材料、および磁性材料
  • 凝縮系物理学


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