2149
Investigation of the Thermal and Photo Sensing Properties of Graphene Oxide and Reduced Graphene Oxide Films Obtained By Spin Coating Method

Wednesday, 1 June 2022: 17:20
West Meeting Room 208 (Vancouver Convention Center)
K. O. Olumurewa (McPherson University, Obafemi Awolowo University) and M. A. Eleruja (Obafemi Awolowo University)
This research reported the thermal and photo sensing properties of graphene oxide (GO) and reduced graphene oxide (RGO) films. In this study, GO and RGO films were obtained by spin coating on soda lime glass using the vertical electrode arrangement. The materials were characterized using FTIR, SEM, EDX and UV visible spectroscopy. As temperature increased to 523K and above, the thermal resistance of GO and RGO tallied. GO showed a higher thermal sensing response of 9.0 compared to RGO which had a maximum thermal sensing response of 2.2. The thermal conductivity of both GO and RGO increased with temperature although RGO typified better thermal conductivity. For GO, a negative temperature coefficient of resistance (NTC) of 0.0032153 Ω/K was obtained which is higher than values obtained in literatures while RGO had a NTC value of 0.00201 Ω/K. Calculated activation energy for GO was 1.75535 x 10-20 JΩ while RGO had an activation energy of 6.37924 x 10-21JΩ. For the photo sensing, the peak photo resistance of GO corresponds to an energy band gap of 3.5 eV while the peak photo resistance of RGO corresponds to a decreased energy band gap of 2.76 eV. RGO film showed intrinsic photoconductivity as the photoconductivity of RGO increased at longer wavelengths. The utilization of GO as photo sensors might be more suitable at the far UV region of between 350 nm- 400 nm. In contrast, RGO showed better suitability for photo sensing in the visible region of the EM spectrum. The photo sensing of both GO and RGO were dominated by inter-band optical transitions in the UV to mid infra-red region. The obtained NTC values over broader temperature range for GO and RGO and the photoconductivity of the materials can promote further utilization in robotics and optical applications.