Dielectric properties and the role of grain boundaries in polycrystalline tetracene at high pressures

The dielectric properties and the role of grain boundaries in polycrystalline tetracene were studied at pressures of up to 21.3 GPa using in situ impedance spectroscopy measurements. Two anomalous changes in some of the electrical parameters (resistance, relaxation frequency and relative permittivit...

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Bibliographic Details
Published in:CrystEngComm 2019, Vol.21 (3), p.457-4512
Main Authors: Wang, Qinglin, Sang, Dandan, Guo, Shitai, Wang, Xiaoli, Wang, Wenjun, Zhang, Bingyuan, Hu, Haiquan, Fan, Quli, Liu, Cailong
Format: Article
Language:English
Subjects:
Dielectric properties
First principles
Grain boundaries
Mathematical analysis
Permittivity
Polarization
Polycrystals
Space charge
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Summary:The dielectric properties and the role of grain boundaries in polycrystalline tetracene were studied at pressures of up to 21.3 GPa using in situ impedance spectroscopy measurements. Two anomalous changes in some of the electrical parameters (resistance, relaxation frequency and relative permittivity) were found at 6.0 and 19.0 GPa, which were related to the structural rearrangement and condensation reaction processes, respectively. Within this pressure range, grain boundaries play an important role in polycrystalline tetracene's conduction mechanism. Based on first-principles calculations, it was found that the variation in bulk resistance under pressure was mainly caused by a change of band gap. Intermolecular interactions are more sensitive to pressure than intramolecular interactions. The decrease in the relative permittivity under pressure indicates the existence of space charge polarization of the interface layer in addition to electronic polarization. Dielectric properties and the role of grain boundaries in polycrystalline tetracene under pressure were investigated using impedance and computational methods.
ISSN:1466-8033
1466-8033
DOI:10.1039/c9ce00961b