Fine tuning of the Fermi level of single-walled carbon nanotubes with onium salts and application for thermoelectric materials was written by Sugiura, Hiroki;Kanazawa, Yoshinori;Nomura, Kimiatsu;Aoai, Toshiaki. And the article was included in Synthetic Metals in 2020.Reference of 628-13-7 This article mentions the following:
Fermi level is one of the most important parameters for control of semiconductor polarity and improvement of thermoelec. performances. Although single-walled C nanotubes (SWCNTs) are promising candidates for thermoelec. materials, control of the Fermi level of SWCNTs with chem. dopants is still challenging. Reported here is the fine-tuning of the Fermi level of SWCNTs with onium salts. The Fermi level of SWCNTs was very sensitive to substituent size on the cation and nucleophilicity of the anion, and the Seebeck coefficients markedly changed between -50μV K-1 and 68μV K-1. The optimum Fermi level of p-type SWCNTs that exhibits the maximum power factor was realized by NH4Cl or pyridine hydrochloride, and the power factor (PF) was improved by ∼7 times as compared with nondoped SWCNTs. SWCNTs doped with onium salts were stable in both p-type and n-type states, and thermoelec. performances did not change >100 days in the air. In the experiment, the researchers used many compounds, for example, Pyridinehydrochloride (cas: 628-13-7Reference of 628-13-7).
Pyridinehydrochloride (cas: 628-13-7) belongs to pyridine derivatives. Pyridine is diamagnetic and has a diamagnetic susceptibility of −48.7 × 10−6 cm3·mol−1.The molecular electric dipole moment is 2.2 debyes. The standard enthalpy of formation is 100.2 kJ·mol−1 in the liquid phase and 140.4 kJ·mol−1 in the gas phase. One of the examples of pyridines is the well-known alkaloid lithoprimidine, which is an A3 adenosine receptor antagonist and N,N-dimethylaminopyridine (DMAP) analog, commonly used in organic synthesis.Reference of 628-13-7