[5p-A502-1~13] 9.5 New functional materials and new phenomena

[5p-A502-1] Electronic Properties of Carrier-Doped COF

Mizue Asda¹, 〇TOSHIKAZU NAKAMURA^1,2, Enquan Jin³, Ping Wang³, Donglin Jiang³ (1.IMS, 2.SOKENDAI, 3.JAIST)

Keywords:magnetism, ESR, COF

COF (Covalent-Organic-Framework) materials are pours crystalline materials, which attract much attention because of their functionalities. COF materials based on the donor(D)-acceptor(A) molecules are unique systems: DA molecules connected by tight covalent bonds within the two-dimensional layers stack to form one-dimensional columns perpendicular to the planes. After photo-excitation to D-A type COFs, an ESR signal originated from the charge-separated state was observed, which could not be observed in isolated molecules. Surprisingly, the lifetime of the photo-excited carriers was extremely long even at R.T. Recently, it was found that several chemically modified COF systems show thermally equivalent paramagnetic state. Theses molecules forms two-dimensional porous network with covalent bond. Aromatic carbon molecules are stacking along perpendicular to the slide. The frontier orbitals are elongated along this direction. The pristine COF system is closed shell. However, applying iodine doping for this system, the color of the sample drastically changes. On the same time, ESR signals suddenly appeared and became larger as the doping time increases. The electronic state of the Py-sp2c may changes with iodine doping. To understand the low-temperature electronic state, the detailed magnetic investigation was carried out. We discuss the itinerant nature of a series of COF materials.