Fabrication of a photoacoustic cell and thermal diffusivity measurement of graphene oxide using photoacoustic spectroscopy

Abstract

Photoacoustic spectroscopy (PAS) is an important technique for the characterization of materials by measuring the heat produced due to the non-radiative transitions. Here, the authors have fabricated a photoacoustic cell and made parametric studies to get maximum signal sensitivity. For the optimum signal, the cavity volume of the sample chamber is found to be 1.763 × 10–6 m3. After optimization of the cell, the thermal diffusivity of hummers method synthesized graphene oxide (GO) powder was measured using laser excitation at 980 nm and it is found to ∼(1.84 ± 0.10) × 10–4 m2/s. Also, the thermal diffusivity of the same sample was measured using 560 and 680 nm excitation wavelengths. No measurable change in thermal diffusivity with excitation wavelength is seen and it confirms that thermal diffusivity is independent of the excitation wavelength. Lastly, photoacoustic spectrum of the GO sample was measured in the 400–1200 nm range and compared with the spectrum of lamp black.