Dielectric properties and the role of grain boundaries in polycrystalline tetracene at high pressures
| Autor: | Shitai Guo, Xiaoli Wang, Quli Fan, Wenjun Wang, Haiquan Hu, Cailong Liu, Dandan Sang, Qinglin Wang, Bingyuan Zhang |
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| Rok vydání: | 2019 |
| Předmět: |
Materials science
Condensed matter physics Band gap Relative permittivity 02 engineering and technology General Chemistry Dielectric 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences 0104 chemical sciences Dielectric spectroscopy chemistry.chemical_compound Tetracene chemistry General Materials Science Grain boundary Crystallite 0210 nano-technology Polarization (electrochemistry) |
| Zdroj: | CrystEngComm. 21:4507-4512 |
| ISSN: | 1466-8033 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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