作者：Xiaoxi Peng, Zhekun Liu, Junan Yao, Hui Li, Yunfei Zhang*, Guoping Yan, Feipeng Du*
关键字：SWCNTs thermoelectric composites
论文来源：期刊
具体来源：Synthetic Metals
发表时间：2020年

Polyethyleneimine (PEI) doped single-walled carbon nanotubes (SWCNTs) composites (PEI/SWCNTs) as n-type organic thermoelectric (TE) materials are important candidates for fabricating flexible TE generators. However, the mechanism of unstable TE behavior for PEI/SWCNTs in the air has been not revealed, which hinders the potential application. In this study, we have investigated the influence of CO₂, H₂O/N₂, H₂O/CO₂, and air on the composition of PEI and TE properties of PEI/SWCNTs. The change of chemical structure shows H₂O and CO₂ have a series of reactions with the amino of PEI to form ammonium salts, which causes the changes in the types of carriers. The Seebeck coeffcient shows that the synergistic effect of H₂O and CO₂ promotes PEI/SWCNTs changing from n-type to p-type. However, the Seebeck coeffcient in dry air shows O₂ almost has no influence on the carrier type of PEI/SWCNTs and the n-type PEI/SWCNTs film can be stable for three months in dry air. Noticeably, reversible transformation between n-type and p-type has been realized via regulating the H₂O and CO₂. The revealed mechanism offers a facile strategy to realize the reversible regulation of TE properties of PEI/SWCNTs and provides a direction for fabricating air-stable n-type PEI/SWCNTs with high TE performance.