Electrical Transport Mechanisms in Graphene Nanoplatelet Doped Polydimethylsiloxane and Application to Ultrasensitive Temperature Sensors

• Published in: ACS applied materials & interfaces Vol. 15; no. 18; pp. 22377 - 22394
• Main Authors: Fernández Sánchez-Romate, Xoan Xosé, del Bosque García, Antonio, Sánchez, María, Ureña, Alejandro
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 10-05-2023
• Subjects: Functional Nanostructured Materials (including low-D carbon); Temperature sensor; Graphene nanoplatelets; Electrical properties; Electrical impedance spectroscopy; PDMS
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.2c22162

The temperature effect on electronic transport mechanisms in graphene nanoplatelet (GNP) doped polydimethylsiloxane (PDMS) for temperature sensing applications has been investigated under electrical impedance spectroscopy (EIS) analysis. AC measurements showed a very prevalent frequency-dependent behavior in low filled nanocomposites due to the lower charge density. In fact, 4 wt % GNP samples showed a nonideal capacitive behavior due to scattering effects. Therefore, the standard RC-LRC circuit varies with the substitution of capacitive elements by CPEs, where a CPE is a constant phase element which denotes energy dissipation. In this regard, the temperature promotes a prevalence of scattering effects, with an increase of resistance and inductance and a decrease of capacitance values in both RC (intrinsic and contact mechanisms) and LRC (tunneling mechanisms) elements and, even, a change from ideal to nonideal capacitive behavior as in the case of 6 wt % GNP samples. In this way, a deeper understanding of electronic mechanisms depending on GNP content and temperature is achieved in a very intuitive way. Finally, a proof-of-concept carried out as temperature sensors showed a huge sensitivity (from 0.05 to 11.7 °C–1) in comparison to most of the consulted studies (below 0.01 °C–1), proving, thus, excellent capabilities never seen before for this type of application.