Alternating current properties of bulk- and nanosheet-graphitic carbon nitride compacts at elevated temperatures

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dc.contributor.authorMaluangnont, Tosapol
dc.contributor.authorPulphol, Phieraya
dc.contributor.authorChaithaweep, Kanokwan
dc.contributor.authorDabsamut, Klichchupong
dc.contributor.authorKobkeatthawin, Thawanrat
dc.contributor.authorSmith, Siwaporn Meejoo
dc.contributor.authorBoonchun, Adisak
dc.contributor.authorVittayakorn, Naratip
dc.date.accessioned2026-08-06T10:42:09Z
dc.date.available2026-08-06T10:42:09Z
dc.date.issued2023-08-23
dc.description.abstractThe investigations of temperature-dependent electrical properties in graphitic carbon nitride (g-C<inf>3</inf>N<inf>4</inf>) 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-C<inf>3</inf>N<inf>4</inf> compacts simply prepared by pelletizing the powder. The bulk sample was synthesized via the direct heating of urea, and the subsequent HNO<inf>3</inf>-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<sup>−5</sup>-3.1 × 10<sup>−5</sup> K<sup>−1</sup>. It is found that bulk- and nanosheet-g-C<inf>3</inf>N<inf>4</inf> were highly insulating (resistivity ρ ∼ 10<sup>8</sup> 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 (10<sup>3</sup>-10<sup>5</sup> Hz). The experimentally determined ϵ′ of bulk-g-C<inf>3</inf>N<inf>4</inf> 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-C<inf>3</inf>N<inf>4</inf> 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.
dc.identifier.citationRsc Advances, 13(36), 25276-25283, 2023
dc.identifier.doi10.1039/d3ra04520j
dc.identifier.issn20462069
dc.identifier.other2-s2.0-85169977386
dc.identifier.urihttps://dspace.kmitl.ac.th/handle/123456789/14592
dc.sourceRsc Advances
dc.titleAlternating current properties of bulk- and nanosheet-graphitic carbon nitride compacts at elevated temperatures
dc.typeArticle

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