Enhanced Goos-Hänchen Shift of SPR Sensor with TMDCs and Doped PANI/Chitosan Composites for Heavy Metal Ions Detection in Aquatic Environment

Abstract

A novel surface plasmon resonance (SPR) sensor with transition metal dichalcogenides (TMDCs) and polyaniline (PANI)/chitosan composite for detection of heavy metal ions in an aquatic environment is proposed and analyzed. The Goos-Hänchen (GH) shift is employed as an important method for analyzing the performance of the SPR sensor. It is theoretically shown that the GH shift can be signi cantly enhanced in the SPR structure silver (Ag) coated with a TMDCs and PANI/CS heterostructure. When the incident light wavelength is 632.8nm, the refractive index of Cu 2+ ion is 1.3516. Through comparison and optimization analysis, when the thickness of MoSe 2 and PANI/chitosan is monolayer and 123 nm, respectively, the maximum GH shift is -2067λ at resonance angle 69.19°. When different Cu 2+ ion concentrations are added into the sample layer, the refractive index of the sample and GH shift of the SPR sensor will change. The maximum sensitivity of 2.425×10 6 λ/RIU is obtained by Ag-WSe 2 -PANI/chitosan structure, which is 463.42 times higher than the traditional SPR Ag lm and 112.84 times higher than Ag-PANI/chitosan structure. The discovery of the Kretschmann structure SPR sensor with 2D material provides a new development direction for the detection of heavy metal ions in an aquatic environment.

Exploration of Illicit Drug Detection Based on Goos–Hänchen Shift

“…This shift serves as an apt detection signal, unaffected by variations in light source intensity [19]. Since its experimental discovery in 1947, GHS has spurred numerous theoretical and empirical studies and has found applications in sensors [20][21][22], optical switches [23,24], and optical storage [25]. Notably, with GHS's tight association with the electromagnetic properties of materials (like refractive index), it is emerging as a detection method in chemical and environmental realms [26,27].…”

“…Notably, with GHS's tight association with the electromagnetic properties of materials (like refractive index), it is emerging as a detection method in chemical and environmental realms [26,27]. Recent research by Min Jin in 2023, for instance, leveraged a specifically designed GHS sensor for detecting aquatic heavy metal ions [20]. Jiangyu Liu explored the feasibility of using a designed terahertz GHS sensor for detecting biological small molecules [26].…”

“…Due to the small value of GHS, it is relatively difficult to measure, so enhancing the GHS displacement has become a research hotspot. SPR sensors based on GHS [20,[28][29][30] have been widely used in the detection field and have achieved good detection sensitivity. However, just like the SERS technology, the SPR enhancement effect depends on the presence of metal nanoparticles or nanofilms, and the impact of precious metals on biological samples is still unknown.…”