Integration of Highly Sensitive Oxygenated Graphene With Aluminum Micro-Interdigitated Electrode Array Based Molecular Sensor for Detection of Aqueous Fluoride Anions

Abstract

High sensitivity and reliability of graphene oxide (GO) integrated with aluminum (Al) micro-interdigitated electrodes (μ-IDEs) patterned on p-Si for the detection of aqueous fluoride anion (F <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-</sup> ) is demonstrated. The strong molecular interaction, hydrogen bonding, and ionic conduction between the oxygen containing functional groups (epoxy (1, 2-ether), hydroxyl, carbonyl, and carboxyl) onto GO and F <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-</sup> are investigated by electrical and optical techniques. The GO/Al (μ-IDEs)/p-Si sensor system shows ~82% increase in the sensing signal for 0.1 ppm GO + F <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-</sup> solution with respect to GO. The response of the sensor for 1, 10, 100, and 1000 ppm of GO + F <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-</sup> solution shows almost 220, 415, 500, and 305 times increase in sensing signal with respect to GO. The significant enhancement in sensor response at lower concentration (0.1-100 ppm) of F <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-</sup> is observed. However, at high concentration (1000 ppm) of F <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-</sup> , the interlayer swelling and the expansion of GO dominate and result the reduction in sensing response of GO/Al (μ-IDEs)/p-Si sensor. The Fourier transform infrared spectroscopy (FT-IR) spectra show the decrease in -OH, C-O-C, and CLO absorption peaks of GO with an increasing aqueous F <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-</sup> concentration, supporting the reduction in sensing response at 1000 ppm. The response of GO/Al (μ-IDEs)/p-Si sensor is favorable for use in graphene-based electronics sensors.