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

High sensitivity and reliability of graphene oxide (GO) integrated with aluminum (Al) micro-interdigitated electrodes (
$\mu $
-IDEs) patterned on p-Si for the detection of aqueous fluoride anion (F
⁻
) 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
⁻
are investigated by electrical and optical techniques. The GO/Al (
$\mu $
-IDEs)/p-Si sensor system shows
$\sim 82$
% increase in the sensing signal for 0.1 ppm GO + F
⁻
solution with respect to GO. The response of the sensor for 1, 10, 100, and 1000 ppm of GO + F
⁻
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
⁻
is observed. However, at high concentration (1000 ppm) of F
⁻
, the interlayer swelling and the expansion of GO dominate and result the reduction in sensing response of GO/Al (
$\mu $
-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
⁻
concentration, supporting the reduction in sensing response at 1000 ppm. The response of GO/Al (
$\mu $
-IDEs)/p-Si sensor is favorable for use in graphene-based electronics sensors.