Hybrid multilayer surface plasmon resonance sensor based on tantalum pentoxide and silver gallium sulfide for ultra-trace detection of lead (II) ions in environmental samples

pollution of water by lead ions (Pb 2 + ) presents a serious health risk and requires sensitive detection of Pb2 + ions based on refractive-index (RI) variations. Hence, the detection of this Pb 2+ ion has been done by employing a surface plasmon resonance (SPR) sensor with a six-layer structure that includes tantalum pentoxide ( 𝑇 𝑎 2 ⁢ 𝑂 5 ), silver (Ag), silver gallium sulfide ( 𝐴 𝑔 𝐺 𝑎 𝑆 2 ) , and black phosphorus (BP) to provide real-time and accurate detection of Pb 2+ ions. The sensor performance was analyzed at a 633 nm wavelength using the transfer matrix method (TMM) and angular interrogation (AI). First, the optimization of the prism and the thickness of the Ag layer was achieved by analyzing the sensing performance of the prism under various prism configurations and different Ag thicknesses, respectively. Next, the effectiveness of the suggested sensor was evaluated by comparing its sensing properties with those of other layered structures. Subsequently, sensitive and precise detection of Pb 2+ ions was performed with the optimized configuration. The proposed sensor showed a strong sensor response with a sensitivity of 335.4655°/RIU, a quality factor (QF) of 202.6044 ( 𝑅 𝐼 𝑈 − 1 ) , and a detection accuracy (DA) of 5.5701. These performance improvements demonstrate that the proposed design has superior detection capabilities compared to traditional SPR sensors. This can be particularly useful for environmental monitoring and the health and safety of people.