Analytical Study of SPR Sensor with Black Phosphorus and Tungsten Diselenide Heterostructure for Milk Adulteration Detection

This investigation introduces a novel bimetallic surface plasmon resonance (SPR) sensor for milk adulteration sensing that depends on the advantageous properties of two-dimensional nanomaterials like black phosphorus (BP), graphene, molybdenum disulfide (MoS₂), molybdenum diselenide (MoSe₂), tungsten disulfide (WS₂), and tungsten diselenide (WSe₂). The performance of bimetallic sensors is shown to be much superior to that of single-layer sensors in terms of both sensitivity and detection accuracy. To get an optimum sensor structure performance, the sensor structure is optimized by incorporating the monolayers of nanomaterials while BP is fixed in each structure and it is used as an evanescent field enhancement layer. The optimized bimetallic sensor structure, i.e., structure 5, consisting of BP and WSe₂, exhibits a sensitivity of 237.2°/RIU and a penetration depth (PD) of 522 nm. Further, proposed sensor claims exceptional attributes, including a moderate limit of detection (LoD = 4.21585 × 10⁻⁶). Thus, the enhanced performance and excellent PD emphasize the perspective of the proposed sensor for sensitive refractive index sensing applications.