The 80th JSAP Autumn Meeting 2019

Presentation information

Oral presentation

Joint Session M » 22.1 Joint Session M "Phonon Engineering"

[19p-E214-1~12] 22.1 Joint Session M "Phonon Engineering"

Thu. Sep 19, 2019 1:15 PM - 4:45 PM E214 (E214)

Tsunehiro Takeuchi(Toyota Technol. Inst.), Takanobu Watanabe(Waseda Univ.), Tsuyohiko Fujigaya(Kyushu Univ.)

2:45 PM - 3:00 PM

[19p-E214-6] Structure and Properties of WO3-x Thin Films (2): Dependence of Thermal Conductivity on Reduced State

〇(M1)Koichi Sakata1, Kai Otani1, Takashi Yagi1,2, Yuichiro Yamashita1,2, Makoto Kashiwagi1, Junjun Jia3, Naoyuki Taketoshi1,2, Yuzo Shigesato1 (1.Aoyama Gakuin Univ., 2.AIST, 3.GCSE, Waseda Univ.)

Keywords:electrochromic materials, tungsten oxide, thermal conductivity

Amorphous tungsten oxide is one of the electrochromic materials that can change their optical properties reversibly between colored and transparent states by electrochemical oxidation-reduction. Tungsten oxide have attached large interest as the thermal switching materials because phase transition to metal takes place at x>0.32 in HxWO3. In this study, we prepared WO3-x films reduced by controlled an O2 flow ratio in the deposition and HxWO3 films reduced by electrochemical reaction, where x was smaller than 0.32. The thermal conductivity was analyzed using a pulsed light heating thermoreflectance apparatus. Thermal conductivities of the WO3-x films controlled to the transmittance of 32%-100% and HxWO3 films applied +0.2V or -0.2V, where the x was smaller than 0.32, showed almost no-changes.