Abstract
Optical sensors with local surface plasmon resonance (LSPR) of noble metal (gold, silver, platinum) nanoparticles have received extensive attention due to their excellent detection performance. Here, we propose an LSPR fiber-optic sensor with a graphene oxide/triangular silver nanoparticle structure. Benefiting from the LSPR characteristics of the silver triangle nanoparticles, the use of triangular silver nanoparticles provides significant sensitivity enhancement. In order to highlight the enhancement of silver triangle nanoparticles, we chose the commonly used silver spherical nanoparticles as a comparison. We used the finite difference time domain method to model and calculate the local electric field and extinction efficiency for the two shapes of silver nanoparticles. The simulation results show that the local electric field intensity of triangular silver nanoparticles is 10 times that of spherical silver nanoparticles, and the extinction efficiency is 4 times that of spherical silver nanoparticles. In the experiment, a U-shaped LSPR fiber sensor with spherical and triangular silver nanoparticles was fabricated. The former has a refractive index sensitivity of 342.7 nm/RIU and the latter has a sensitivity of 1116.8 nm/RIU. Even if there is temperature interference during the detection process, the detection result will not produce a large error.
Highlights
In recent years, the latest progress of nanotechnology has brought new developments for localized surface plasmon resonance (LSPR) fiber optical sensors
The simulation results show that the local electric field intensity of triangular silver nanoparticles is 10 times that of spherical silver nanoparticles, and the extinction efficiency is 4 times that of spherical silver nanoparticles
Localized surface plasmon resonance refers to the absorption and scattering characteristics of light exhibited by noble metal nanoparticles in UV–visible region
Summary
The latest progress of nanotechnology has brought new developments for localized surface plasmon resonance (LSPR) fiber optical sensors. The extinction range produced by the LSPR phenomenon is affected by the shape, size, material, and refractive index of the surrounding medium.. The extinction range produced by the LSPR phenomenon is affected by the shape, size, material, and refractive index of the surrounding medium.1 Due to it can realize real-time, repeatable and highly sensitive detection of target, LSPR sensors have been widely used to detect chemical macromolecules and biological analytes at low concentrations, such as environmental safety monitoring and early detection of cancer.. In order to improve the sensitivity of LSPR fiber optic sensor, many researchers have studied the coating materials of LSPR sensor, and their researches show that the shape and material of nanoparticles have a great influence on the sensitivity.. In this paper, according to the LSPR optical properties of metal nanoparticles, we propose a graphene oxide/triangular silver nanoparticle U-type fiber LSPR sensor. The simulation results were verified by experiments and the practicality of the triangular silver nanoparticle sensor was further tested
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