A cyano-rich small molecule dopant for organic thermoelectrics

• Published in: Organic electronics Vol. 87; p. 105978
• Main Authors: Tu, Kuan-Heng, Wang, Yang, Kiyota, Yasuhiro, Iwahashi, Takashi, Ouchi, Yukio, Mori, Takehiko, Michinobu, Tsuyoshi
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.12.2020
• Subjects: Chemical doping; Cyano-rich small molecules; Electrical conductivities; Organic semiconductors; Organic thermoelectrics; Cyano-rich small molecules; Organic semiconductors; Chemical doping; Electrical conductivities; Organic thermoelectrics
• ISSN: 1566-1199; 1878-5530
• DOI: 10.1016/j.orgel.2020.105978

The development of new dopants makes a great contribution to the recent advances in organic semiconductors. In this work, a cyano-rich small molecule, i.e., octacyano[4]dendralene containing bis-1,1,4,4-tetracyanobutadiene unit (TCBD), was used as a p-dopant of organic thermoelectric devices attributed to it being strongly electron-accepting and its high chemical stability. Poly(3,4-ethylenedioxythiophene) (PEDOT) was successfully doped by the TCBD dopant, and the degree of doping was comprehensively characterized by ultraviolet–visible–near infrared (UV–Vis–NIR), Fourier transform infrared (FT-IR) spectroscopy, atomic force microscopy (AFM) images, ultraviolet photoelectron spectroscopy (UPS) and X-ray photoelectron spectroscopy (XPS) measurements. The PEDOT:TCBD complex achieved its best electrical conductivity and power factor when the TCBD concentration was 18 mol%. Furthermore, a practical thermoelectric generator was constructed by the combination of the p-type PEDOT:TCBD complex and n-type constantan. [Display omitted] •A cyano-rich TCBD molecule was successfully employed as a p-dopant of PEDOT for the first time.•The successful doping was characterized by a series of spectroscopic measurements.•The doped complex achieved the best electrical conductivity and thermoelectric power factor at the doping ratio of 18 mol%.•A thermoelectric generator was constructed by the combination of the p-type PEDOT:TCBD complex and n-type constantan.