Strong Suppression of Thermal Conductivity in the Presence of Long Terminal Alkyl Chains in Low‐Disorder Molecular Semiconductors

• DOI: 10.1002/adma.202008708
• Publication Date: 2021-08-03T16:09:40Z
• Authors: Ekaterina Selezneva; Alexandre Vercouter; Guillaume Schweicher; Vincent Lemaur; Katharina Broch; Aleandro Antidormi; Kazuo Takimiya; Veaceslav Coropceanu; Jean‐Luc Brédas; Claudio Melis; Jérôme Cornil; Henning Sirringhaus
• Keywords: Organic semiconductor; Charge carrier

While the charge transport properties of organic semiconductors have been extensively studied over recent years, field organics-based thermoelectrics is still limited by a lack experimental data on thermal and understanding associated structure-property relationships. To fill this gap, comprehensive theoretical investigation lattice conductivity in polycrystalline thin films dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (Cn-DNTT-Cn with n = 0, 8) reported. Strikingly, appears to be much more isotropic than transport, which confined 2D molecular layers. A direct comparison between measurements (3ω-Völklein method) estimations (approach-to-equilibrium dynamics (AEMD) indicates that in-plane strongly reduced presence long terminal alkyl chains. This evolution can rationalized strong localization intermolecular vibrational modes C8-DNTT-C8 unsubstituted DNTT cores, as evidenced mode analysis. Combined enhanced alkylated systems, opens possibility decouple electron phonon these materials, provides great potential for enhancing thermoelectric figure merit ZT.