Investigating the effect of surface termination and thickness of MXene on the detection response of the SPR sensor using FDTD simulation

Surface plasmon resonance (SPR) is an optical-based detection technique that is of great interest in research because of its rapid detection and label-free features. Current SPR sensor development focuses on modifying the sensing surface for maximum bioreceptor and target immobilization. In this research, we proposed SPR sensor with the Kretschmann configuration modified by adding immobilization layers using a few layers of MXene (Ti3C2T2). MXene is an alternative two-dimensional material suitable for sensors because it has surface termination (T-2) which active to immobilize the target. The different surface termination (T = O, OH, F) and number of MXene layers was added on the SPR sensor to obtained the optimum parameters of MXene application. Using Finite-Difference Time-Domain (FDTD) method, the SPR sensor is simulated on a different refractive index background which is assumed as the analyte. The different surface termination produces different SPR curves at the same refractive index conditions, the changes are found in the position of the SPR angle and the width of the curve. Thus, the results of surface termination variations are evaluated based on the full-width half-maximum (FWHM) of the curve which indicates the detection accuracy. Meanwhile, the optimum number of MXene layers was evaluated from the sensitivity value of the MXene-modified SPR sensor to changes in refractive index from 1.33 to 1.34. The result shows that the optimum detection performance was obtained from the application of six layers MXene with surface termination F-2(Ti3C2F2). This configuration resulted a sensitivity of 150.131 degrees/RIU and the LOD is 0.01633 RIU.