Sensitivity Enhancement by the Ag/Few-Layer Black Phosphorus/Mxene Structure in Surface Plasmon Resonance Biochemical Sensor

A highly sensitive surface plasmon resonance biosensor composed of the hybrid black phosphorus-MXene (Ti₃C₂T_x) structure and Ag bimetal layers is designed and investigated analytically by the angular interrogation technique. The use of bilayer Ag enhances the sensitivity compared to a single metal layer. Black phosphorus enhances the light-matter interaction due to its layer-dependent direct and tunable bandgap. The thickness of the BP and Ag layers and the number of Ti₃C₂T_x sheets are optimized to maximize the sensitivity. It covers a wide range of refractive index (RI) from 1.330 to 1.335, for which an optimized angular sensitivity of 450°/RIU is observed from the Ag bimetal MXene-based SPR biosensor. It can be fabricated as a sensor chip for efficient sensing of analytes or biochemical molecules by carefully controlling the surface termination of Ti₃C₂T_x. The encouraging results from this research underscore the high potential of this structure in surface plasmon resonance biosensors, which is crucial for the early detection of biological diseases. By overcoming the limitations of traditional sensors, this innovative structure boasts both high sensitivity and rapid response speed, thereby demonstrating the remarkable potential for market adoption and application in biomedical research, ultimately enhancing the effectiveness of disease treatment through earlier interventions. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2024.