Crystal Structure, Spin Polarization, Solid-State Electrochemistry, and High n-Type Carrier Mobility of a Paramagnetic Semiconductor: Vanadyl Tetrakis(thiadiazole)porphyrazine

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• 作者：Yasuhito Miyoshi ; Kouji Takahashi ; Takuya Fujimoto ; Hirofumi Yoshikawa ; Michio M. Matsushita ; Yukio Ouchi ; Mikael Kepenekian ; Vincent Robert ; Maria Pia Donzello ; Claudio Ercolani ; Kunio Awaga
• 刊名：Inorganic Chemistry
• 出版年：2012
• 出版时间：January 2, 2012
• 年：2012
• 卷：51
• 期：1
• 页码：456-462
• 全文大小：487K
• 年卷期：v.51,no.1(January 2, 2012)
• ISSN：1520-510X

文摘

We report the synthesis, crystal structure, and magnetic, electrochemical, and carrier-transport properties of vanadyl tetrakis(thiadiazole)porphyrazine (abbreviated as VOTTDPz) with S = ¹/₂. X-ray crystal analysis reveals two polymorphs, the 伪 and 尾 forms; the former consists of a 1D regular 蟺 stacking, while the latter forms a 2D 蟺 network. Molecular orbital calculations suggest a V⁴⁺(d¹) ground state and a characteristic spin polarization on the whole molecular skeleton. The temperature dependence of the paramagnetic susceptibility of the 伪 form clearly indicates a ferromagnetic interaction with a positive Weiss constant of 胃 = 2.4 K, which is well-explained by McConnell鈥檚 type I mechanism. VOTTDPz forms amorphous thin films with a flat and smooth surface, and their cyclic voltammogram curves indicate a one-electron reduction process, which is highly electrochromic, because of a reduction of the porphyrazine 蟺 ring. Thin-film field-effect transistors of VOTTDPz with ionic-liquid gate dielectrics exhibit n-type performance, with a high mobility of 渭 = 2.8 脳 10^鈥? cm² V^鈥? s^鈥? and an on/off ratio of 10⁴, even though the thin films are amorphous.