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Development of Purely Organic Superconductors
Published in Toshio Naito, Functional Materials, 2019
CT-type purely organic superconductors, β″-(BEDT-TTF)2SF5CH2CF2SO3, κ-(BEDT-TTF)2CF3SO3, (BETS)2(Cl2TCNQ), and (EtDTET)(TCNQ), were successfully developed. The strategy of these organic superconductors is simple, namely, they consist of a combination of an organic electron donor and an organic monoanion or an electron acceptor. Closely related materials of these superconductors were also yielded, such as β″-(BEDT-TTF)2SF5CHFCF2SO3, β″-(BEDT-TTF)2SF5CH2SO3, β″-(BEDT-TTF)2SF5CHFSO3, and (BETS)2(Br2TCNQ) [214, 229–232]. However, the signature of superconductivity has not been detected in the related materials thus far. These results indicate the difficulty in producing purely organic superconductors. Recently, brand-new molecular conductors have been reported. Single-component organic units connected by hydrogen bonding exhibited high electrical conductivity and metallic behavior under pressure [233]. Metallic behavior down to 4 K under ambient conditions was probed in ammonium salts of the TTP donor bearing a carboxylate group using solid-state 1H nuclear magnetic resonance (NMR) measurement [234]. These brand-new conductors will become candidates for purely organic superconductors.
Electronic structures and spectral characteristics of five C28 fullerene and C30 fullerene isomers by XPS and NEXAFS spectra
Published in Molecular Physics, 2021
Ruo-Yu Wang, Huan-Yu Ji, Xiu-Neng Song, Yong Ma, Chuan-Kui Wang
C and C fullerenes have made corresponding progress in theoretical and experimental research, Paul provided the possibility for the preparation of C and C [10], the C phase exhibits superior separation ability for fullerenes [11], and the Li-doped C intercalated phthalocyanine covalent organic frameworks (C-Pc-PBBA COFs) have good hydrogen storage capacity for the D symmetry [12]. Meanwhile, Breda forward that C fullerene is a possible room temperature organic superconductor [13]. In recent years, C and C have been widely used in various aspects, which have become the important components of the endohedral metallofullerenes (EMFs) [14–16]. Through the research of Adjizian et al. [17], the two symmetrical types of C fullerene (T and D) and the three symmetrical types of C (C, C and D) can be distinguished by IR roughly, and the theoretical energy difference is given, but its work is not perfect. In addition, the electronic and structural properties of the five isomers of C and C fullerenes have also been studied [18–20]. As for X-ray photoelectron spectroscopy (XPS), it describes the ionisation of core electrons, so it reflects the information of the core orbitals, while near-edge X-ray absorption fine structure (NEXAFS) describes the transition of excited core electrons to the unoccupied orbital, so it mainly reflects the information of the unoccupied orbitals. In the past, the XPS and NEXAFS have demonstrated strong ability in the identification of isomers in a variety of fullerene molecules, such as C [21], C [22], C [23], C [24], C [25] and their chlorinated species. In these studies, NEXAFS showed stronger isomer dependence than XPS.