Anharmonic Lattice Vibrations in Small-Molecule Organic Semiconductors

Anharmonic Lattice Vibrations in Small-Molecule Organic Semiconductors

© 2020 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bibliographische Detailangaben
Veröffentlicht in:Advanced materials (Deerfield Beach, Fla.). - 1998. - 32(2020), 10 vom: 11. März, Seite e1908028
1. Verfasser: Asher, Maor (VerfasserIn)
Weitere Verfasser: Angerer, Daniel, Korobko, Roman, Diskin-Posner, Yael, Egger, David A, Yaffe, Omer
Format: Online-Aufsatz
Sprache:English
Veröffentlicht: 2020
Zugriff auf das übergeordnete Werk:Advanced materials (Deerfield Beach, Fla.)
Schlagworte:Journal Article first-principles calculations low-frequency Raman modes oligoacenes polarization-orientation Raman spectroscopy small-molecule organic semiconductors
Beschreibung
Zusammenfassung:© 2020 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
The intermolecular lattice vibrations in small-molecule organic semiconductors have a strong impact on their functional properties. Existing models treat the lattice vibrations within the harmonic approximation. In this work, polarization-orientation (PO) Raman measurements are used to monitor the temperature-evolution of the symmetry of lattice vibrations in anthracene and pentacene single crystals. Combined with first-principles calculations, it is shown that at 10 K, the lattice dynamics of the crystals are indeed harmonic. However, as the temperature is increased, specific lattice modes gradually lose their PO dependence and become more liquid-like. This finding is indicative of a dynamic symmetry breaking of the crystal structure and shows clear evidence of the strongly anharmonic nature of these vibrations. Pentacene also shows an apparent phase transition between 80 and 150 K, indicated by a change in the vibrational symmetry of one of the lattice modes. These findings lay the groundwork for accurate predictions of the electronic properties of high-mobility organic semiconductors at room temperature
Beschreibung:Date Revised 30.09.2020
published: Print-Electronic
Citation Status PubMed-not-MEDLINE
ISSN:1521-4095
DOI:10.1002/adma.201908028