Alternating current properties of bulk- and nanosheet-graphitic carbon nitride compacts at elevated temperatures
Issued Date
2023-08-23
Resource Type
eISSN
20462069
Scopus ID
2-s2.0-85169977386
Journal Title
RSC Advances
Volume
13
Issue
36
Start Page
25276
End Page
25283
Rights Holder(s)
SCOPUS
Bibliographic Citation
RSC Advances Vol.13 No.36 (2023) , 25276-25283
Suggested Citation
Maluangnont T., Pulphol P., Chaithaweep K., Dabsamut K., Kobkeatthawin T., Smith S.M., Boonchun A., Vittayakorn N. Alternating current properties of bulk- and nanosheet-graphitic carbon nitride compacts at elevated temperatures. RSC Advances Vol.13 No.36 (2023) , 25276-25283. 25283. doi:10.1039/d3ra04520j Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/90013
Title
Alternating current properties of bulk- and nanosheet-graphitic carbon nitride compacts at elevated temperatures
Other Contributor(s)
Abstract
The investigations of temperature-dependent electrical properties in graphitic carbon nitride (g-C3N4) have been largely performed at/below room temperature on devices commonly fabricated by vacuum techniques, leaving the gap to further explore its behaviors at high-temperature. We reported herein the temperature dependence (400 → 35 °C) of alternating current (AC) electrical properties in bulk- and nanosheet-g-C3N4 compacts simply prepared by pelletizing the powder. The bulk sample was synthesized via the direct heating of urea, and the subsequent HNO3-assisted thermal exfoliation yielded the nanosheet counterpart. Their thermal stability was confirmed by variable-temperature X-ray diffraction, demonstrating reversible interlayer expansion/contraction upon heating/cooling with the thermal expansion coefficient of 2.2 × 10−5-3.1 × 10−5 K−1. It is found that bulk- and nanosheet-g-C3N4 were highly insulating (resistivity ρ ∼ 108 Ω cm unchanged with temperature), resembling layered van der Waals materials such as graphite fluoride but unlike electronically insulating oxides. Likewise, the dielectric permittivity ϵ′, loss tangent tan δ, refractive index n, dielectric heating coefficient J, and attenuation coefficient α, were weakly temperature- and frequency-dependent (103-105 Hz). The experimentally determined ϵ′ of bulk-g-C3N4 was reasonably close to the in-plane static dielectric permittivity (8 vs. 5.1) deduced from first-principles calculation, consistent with the anisotropic structure. The nanosheet-g-C3N4 exhibited a higher ϵ′ ∼ 15 while keeping similar tan δ (∼0.09) compared to the bulk counterpart, demonstrating its potential as a highly insulating, stable dielectrics at elevated temperatures.