Strong suppression of thermal conductivity in the presence of long terminal alkyl chains in low-disorder molecular semiconductors
Selezneva, Ekaterina (University of Cambridge. Optoelectronics Group)
Vercouter, Alexandre (University of Mons. Laboratory for Chemistry of Novel Materials)
Schweicher, Guillaume (University of Cambridge. Optoelectronics Group)
Lemaur, Vincent (University of Mons. Laboratory for Chemistry of Novel Materials)
Broch, Katharina (Universität Tübingen. Institut für Angewandte Physik)
Antidormi, Aleandro (Institut Català de Nanociència i Nanotecnologia)
Takimiya, Kazuo (RIKEN Center for Emergent Matter Science)
Coropceanu, Veaceslav (Georgia Institute of Technology. School of Chemistry and Biochemistry)
Brédas, Jean-Luc (The University of Arizona. Department of Chemistry and Biochemistry)
Melis, Claudio (Universita di Cagliari. Dipartimento di Fisica)
Cornil, Jerome (University of Mons. Laboratory for Chemistry of Novel Materials)
Sirringhaus, Henning (University of Cambridge. Optoelectronics Group)

Data:	2021
Resum:	While the charge transport properties of organic semiconductors have been extensively studied over the recent years, the field of organics-based thermoelectrics is still limited by a lack of experimental data on thermal transport and of understanding of the associated structure-property relationships. To fill this gap, a comprehensive experimental and theoretical investigation of the lattice thermal conductivity in polycrystalline thin films of dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (Cn-DNTT-Cn with n = 0, 8) semiconductors is reported. Strikingly, thermal conductivity appears to be much more isotropic than charge transport, which is confined to the 2D molecular layers. A direct comparison between experimental measurements (3ω-Völklein method) and theoretical estimations (approach-to-equilibrium molecular dynamics (AEMD) method) indicates that the in-plane thermal conductivity is strongly reduced in the presence of the long terminal alkyl chains. This evolution can be rationalized by the strong localization of the intermolecular vibrational modes in C8-DNTT-C8 in comparison to unsubstituted DNTT cores, as evidenced by a vibrational mode analysis. Combined with the enhanced charge transport properties of alkylated DNTT systems, this opens the possibility to decouple electron and phonon transport in these materials, which provides great potential for enhancing the thermoelectric figure of merit ZT.
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	Molecular dynamics ; Organic semiconductors ; Thermal conductivity ; Thermoelectrics
Publicat a:	Advanced materials, Vol. 33, issue 37 (Sep. 2021) , art. 2008708, ISSN 1521-4095

DOI: 10.1002/adma.202008708
PMID: 34342927

8 p, 829.7 KB

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