N-Type Organic Thermoelectrics of Donor-Acceptor Copolymers Improved Power Factor by Molecular Tailoring of the Density of States

N-Type Organic Thermoelectrics of Donor-Acceptor Copolymers : Improved Power Factor by Molecular Tailoring of the Density of States

© 2018 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Détails bibliographiques
Publié dans:Advanced materials (Deerfield Beach, Fla.). - 1998. - 30(2018), 44 vom: 26. Nov., Seite e1804290
Auteur principal: Liu, Jian (Auteur)
Autres auteurs: Ye, Gang, Zee, Bas van der, Dong, Jingjin, Qiu, Xinkai, Liu, Yuru, Portale, Giuseppe, Chiechi, Ryan C, Koster, L Jan Anton
Format: Article en ligne
Langue:English
Publié: 2018
Accès à la collection:Advanced materials (Deerfield Beach, Fla.)
Sujets:Journal Article donor-acceptor copolymers electrical conductivity and density of states n-type doping solution processing
Description
Résumé:© 2018 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
It is demonstrated that the n-type thermoelectric performance of donor-acceptor (D-A) copolymers can be enhanced by a factor of >1000 by tailoring the density of states (DOS). The DOS distribution is tailored by embedding sp2 -nitrogen atoms into the donor moiety of the D-A backbone. Consequently, an electrical conductivity of 1.8 S cm-1 and a power factor of 4.5 µW m-1 K-2 are achieved. Interestingly, an unusual sign switching (from negative to positive) of the Seebeck coefficient of the unmodified D-A copolymer at moderately high dopant loading is observed. A direct measurement of the DOS shows that the DOS distributions become less broad upon modifying the backbone in both pristine and doped states. Additionally, doping-induced charge transfer complexes (CTC) states, which are energetically located below the neutral band, are observed in DOS of the doped unmodified D-A copolymer. It is proposed that charge transport through these CTC states is responsible for the positive Seebeck coefficients in this n-doped system. This is supported by numerical simulation and temperature dependence of Seebeck coefficient. The work provides a unique insight into the fundamental understanding of molecular doping and sheds light on designing efficient n-type OTE materials from a perspective of tailoring the DOS
Description:Date Completed 05.11.2018
Date Revised 30.09.2020
published: Print-Electronic
Citation Status PubMed-not-MEDLINE
ISSN:1521-4095
DOI:10.1002/adma.201804290