Efficient Solution-Processed n-Type Small-Molecule Thermoelectric Materials Achieved by Precisely Regulating Energy Level of Organic Dopants

Dafei Yuan; Dazhen Huang; Cheng Zhang; Ye Zou; Chong-An Di; Xiaozhang Zhu; Daoben Zhu

doi:10.1021/acsami.7b07282

Efficient Solution-Processed n-Type Small-Molecule Thermoelectric Materials Achieved by Precisely Regulating Energy Level of Organic Dopants

ACS Appl Mater Interfaces. 2017 Aug 30;9(34):28795-28801. doi: 10.1021/acsami.7b07282. Epub 2017 Aug 18.

Authors

Dafei Yuan^{1

2}, Dazhen Huang^{1

2}, Cheng Zhang^{1

2}, Ye Zou¹, Chong-An Di^{1

2}, Xiaozhang Zhu^{1

2}, Daoben Zhu^{1

2}

Affiliations

¹ Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, People's Republic of China.
² University of Chinese Academy of Sciences , Beijing 100190, People's Republic of China.

PMID: 28800218
DOI: 10.1021/acsami.7b07282

Abstract

To achieve efficient n-type doping, three dopants, 2-Cyc-DMBI-H, (2-Cyc-DMBI)₂, and (2-Cyc-DMBI-Me)₂, with precisely regulated electron-donating ability were designed and synthesized. By doping with a small-molecule 2DQTT-o-OD with high electron mobility, an unexpectedly high power factor of 33.3 μW m^-1 K^-2 was obtained with the new dopant (2-Cyc-DMBI-Me)₂. Notably, with the intrinsically low lateral thermal conductivity of 0.28 W m^-1 K^-1, the figure of merit was determined to be 0.02 at room temperature. Thus, we have demonstrated that small molecules with high electron mobility and low-lying LUMO energy levels can achieve high doping efficiency and excellent thermoelectric properties by doping with n-type dopants featuring highly matched energy levels and excellent miscibility.

Keywords: energy level; n-type doping; organic thermoelectrics; small molecule; solution-processed.