Improved ZnO-Ag-graphene oxide surface plasmon resonance organic sensor

This study investigates the detection of organic compounds using a surface plasmon resonance (SPR) sensor comprising Zinc oxide (ZnO), Silver (Ag), and graphene oxide (GO) layers. Graphene oxide is chosen as topmost layer due to its impressive attributes, including a large surface area, robust light absorption, thermal stability, and biocompatibility. By optimizing the thickness of the ZnO and Ag, the performance of the sensor is enhanced. The proposed sensor configuration significantly improved the sensitivity and obtained the maximal value of 215°/RIU at minimum reflectance (R min ). At a ZnO thickness of 20 nm and Ag thickness of 35 nm, the sensor achieves maximal sensitivity of 222.79/RIU for detecting the n-octane organic compound. This improved sensor design shows efficacy in detecting analytes with refractive index (RI) variations ranging from 1.33 to 1.39. Additionally, the proposed sensor demonstrated a limit of detection (LoD) of 5.65 RIU and figure of merit (FoM) of around 50.75/RIU, highlighting its high sensitivity, and detection accuracy. Furthermore, substantial penetration depths (PDs) of 219.71 nm for water and 211.11 nm for n-octane are obtained. This analysis highlights the exceptional performance of the proposed sensor, rendering it highly suitable for sensing applications in both industrial and biomedical domains.