[12a-N106-1~9] 22.1 Joint Session M "Phonon Engineering"

[12a-N106-4] Evaluation of thermophysical properties of single crystals of a π-stacked columnar assembly by thermal conductivity, diffusivity, and specific heat measurements

〇Ryosuke Takehara^1,3, Meguya Ryu^2,3, Suguru Kitani¹, Yoshiaki Shoji^1,3, Tomoaki Nishino^1,3, Junko Morikawa^1,3, Hitoshi Kawaji¹, Takanori Fukushima^1,3 (1.Tokyo Tech, 2.AIST, 3.CREST-JST)

Keywords:thermal conductivity and diffusivity, organic crystal, pi-stacked structure

Using single crystals of a triphenylene derivative as a motif, we have investigated how π-stacked structures of organic molecules contribute to thermal transport properties. Measurements on the anisotropy of the thermal diffusivity of a single crystalline sample suggested that the contribution of the π-stacking to the thermal transport properties is small. Specific heat measurements were performed to confirm whether the thermal diffusivity and thermal conductivity results are consistent with each other. The specific heat of the single crystals decreased monotonically from room temperature to a low temperature, and detailed analysis of the obtained data showed that isolated molecular vibrations, rather than lattice vibrations, more contribute to the behavior of the specific heat.