start-ver=1.4 cd-journal=joma no-vol=8 cd-vols= no-issue=22 article-no= start-page=7422 end-page=7435 dt-received= dt-revised= dt-accepted= dt-pub-year=2020 dt-pub=20200418 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Synthesis of [7]phenacene incorporating tetradecyl chains in the axis positions and its application in field-effect transistors en-subtitle= kn-subtitle= en-abstract= kn-abstract=Field-effect transistors (FETs) were fabricated using a new type of phenacene molecule, 3,12-ditetradecyl[7]phenacene ((C14H29)2-[7]phenacene), and solid gate dielectrics or an electric double layer (EDL) capacitor with an ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate (bmim[PF6])). The new molecule, (C14H29)2-[7]phenacene, was efficiently synthesized via the Mallory photoreaction. Its crystal structure and electronic properties were determined, using X-ray diffraction, scanning tunneling microscopy/spectroscopy (STM and STS), absorption spectroscopy, and photoelectron yield spectroscopy, which showed a monoclinic crystal lattice (space group P21 (no. 4)) and an energy gap of ?3.0 eV. The STM image clearly showed the molecular structure of (C14H29)2-[7]phenacene, as well as the closed molecular stacking, indicative of a strong fastener effect between alkyl chains. The X-ray diffraction pattern of thin films of (C14H29)2-[7]phenacene formed on a SiO2/Si substrate suggested that the molecule stood on the surface with an inclined angle of 30 with respect to the normal axis of the surface. The FET properties were recorded in two-terminal measurement mode, showing p-channel normally-off characteristics. The averaged values of field-effect mobility, , were 1.6(3) cm2 V?1 s?1 for a (C14H29)2-[7]phenacene thin-film FET with a SiO2 gate dielectric and 6(4) ~ 10?1 cm2 V?1 s?1 for a (C14H29)2-[7]phenacene thin-film EDL FET with bmim[PF6]. Thus, higher FET performance was obtained with an FET using a thin film of (C14H29)2-[7]phenacene compared to parent [7]phenacene. This study could pioneer an avenue for the realization of high-performance FETs through the addition of alkyl chains to phenacene molecules. en-copyright= kn-copyright= en-aut-name=OkamotoHideki en-aut-sei=Okamoto en-aut-mei=Hideki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=HamaoShino en-aut-sei=Hamao en-aut-mei=Shino kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=KozasaKeiko en-aut-sei=Kozasa en-aut-mei=Keiko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=WangYanan en-aut-sei=Wang en-aut-mei=Yanan kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=KubozonoYoshihiro en-aut-sei=Kubozono en-aut-mei=Yoshihiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=PanYong-He en-aut-sei=Pan en-aut-mei=Yong-He kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=YenYu-Hsiang en-aut-sei=Yen en-aut-mei=Yu-Hsiang kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=HoffmannGermar en-aut-sei=Hoffmann en-aut-mei=Germar kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=TaniFumito en-aut-sei=Tani en-aut-mei=Fumito kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= en-aut-name=GotoKenta en-aut-sei=Goto en-aut-mei=Kenta kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=10 ORCID= affil-num=1 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= affil-num=5 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= affil-num=6 en-affil=Department of Physics & Center for Quantum Technology, National Tsing Hua University kn-affil= affil-num=7 en-affil=Department of Physics & Center for Quantum Technology, National Tsing Hua University kn-affil= affil-num=8 en-affil=Department of Physics & Center for Quantum Technology, National Tsing Hua University kn-affil= affil-num=9 en-affil=Institute for Materials Chemistry and Engineering, Kyushu University kn-affil= affil-num=10 en-affil=Institute for Materials Chemistry and Engineering, Kyushu University kn-affil= END