High performance n-type thermoelectric material based on naphthalenediimide radical anions

作者：Zhao, D.; Jiang, Q.; Jia, Y.; Zhou, J.; Zheng, N.; Hu, D.^*; Ma, Y.^*

来源：Materials Today Energy, 2021, 21: 100710.

DOI：10.1016/j.mtener.2021.100710

• Phenyl lithium
• Doping
• Solution processing
• Electrical conductivity
• Seebeck coefficient

An ideal organic thermoelectric (TE) material should possess features that would be low-cost, of high performance, easy to process, and non-toxic, but it is rare to find materials that meet these requirements. Naphthalenediimide (NDI), as a common and cheap industrial pigment, displays strong intermolecular inaction and good n-type semiconductor character. However, due to the strong interaction of 7C -7C and hydrogen bond interaction, NDI usually exhibited poor solubility, making it difficult to process in solu-tion. Herein, we demonstrated that the unsubstituted NDI could form a suspension mixed with NDI radical anion state by phenyl lithium doping, which consequently can be used to prepare dense film by drop-casting for TE application. More importantly, by optimizing the doping ratio, the TE film reached electrical conductivity of 0.11 S cm(-1) and Seebeck coefficient of-1289 mu V K-1. Eventually, a high power factor up to 18.8 mu W m(-1) K-2 and ZT value of 0.053 was obtained, which is one of the best TE perfor-mance achieved in n-type NDI-based TE materials. This work suggests the simple strategy of utilizing commercially mature molecules to develop organic TE materials with high performance.

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