Complex Impedance Spectra of Polymer‐Derived Silicon Oxycarbides

Abstract

The complex impedance spectra of polymer-derived amorphous silicon oxycarbides synthesized at different temperatures are reported. Analysis of the spectra using equivalent circuit models showed that the conduction of current is dominantly through the matrix and free carbon in series, instead of through the matrix or free carbon only. We found that the conductivity of both matrix and free-carbon phase increases with increasing synthesis temperature, whereas the relaxation time of the matrix is much shorter than that of the free carbon. The results are correlated with the structures of the materials.

Evolution in the Electronic Structure of Polymer‐derived Amorphous Silicon Carbide

“…The disks were finally pyrolyzed at different temperatures of 1000°C, 1100°C, 1200°C, and 1300°C for 4 h under the protection of flowing ultrahigh purity argon. The obtained materials were amorphous with the composition of ~SiC 1.45 O 0.08 , independent of pyrolysis temperature; the small amount of oxygen is likely due to the contamination during material synthesis …”

Frequency-dependent conductive behavior of polymer-derived amorphous silicon carbonitride

“…Haluschka et al [18] reported a strong frequency-dependent conductivity in polymerderived silicon carbonitride, and attributed the phenomenon to a large polaron tunneling process [18]. Wang and co-workers [24] reported the complex impedance spectra of the polymer-derived silicon oxycarbide ceramics. However, AC conductive behavior has never been investigated in detail for polymer-derived ceramics.…”

N-doped polymer-derived Si(N)OC: The role of the N-containing precursor

“…3,4 Such a unique nanostructure conveys to these materials an exceptional mix of properties combining high elastic modulus and excellent chemical durability, [5][6][7] with optical, 8 electrochemical, 9 and electrical properties 10 which make SiOCs good candidate materials for LED, 11 anodes for Li-ion batteries 12,13 and pressure and temperature sensors for harsh environments, 14 respectively. The amount and structure of the free carbon phase of silicon oxycarbides have been shown to influence many different properties such as the stability of the amorphous network and its crystallization kinetics, 15 the electrical 16,17 and optical properties, 18 as well as the Li storage capacity when SiOCs are used as anodes for Li-ion batteries. 19 Accordingly, the free carbon phase present in the SiOC nanostructure has been extensively characterized using different techniques 1 and also modeled by ab initio molecular dynamic simulation.…”