Keywords: DNA; graphene; bio-supercapacitor

Abstract

This work reports on the formation of rGO/ssDNA composite by stabilization of rGO sheets in an aqueous solution containing ssDNA extracted from baker’s yeast culture. The as-formed rGO/ssDNA composite was verified using spectroscopic and microscopic techniques, including Fourier transform infrared (FTIR), Raman, and photoluminescence (PL) spectroscopies, and field emission scanning electron microscopye (FESEM). Physical investigations showed the successful stabilization of rGO suspension by ssDNA for more than a month without the rGO sheets precipitating. The highly charged backbone of ssDNA comprising phosphate groups, nucleic-bases, and sugar molecules contributed to the rGO stabilization and this could be a potential electrode material for a charge storage supercapacitor. Electrochemical investigations confirmed the electrochemical double-layer capacitance behavior of rGO/ssDNA composite in KOH electrolyte, where a nearly 2-fold capacitance enhancement was observed compared to pure rGO. The oxygen residues on ssDNA were shown to contribute to the electrochemically active surface area of rGO/ssDNA. By virtue of the approach simplicity of its preparation and its being environmentally benign, it the proposed material can be considered as a promising candidate for practical applications of as a bio-supercapacitors after further processing.