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, μ, 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