abstract
In this work, we present a detailed numerical and experimental investigation of highly sensitive optical fiber sensors based on localized surface plasmon resonance (LSPR). These sensors are enhanced by the deposition of nanoparticles (NPs) and nanostars (NSs) onto uncladded silica multi-mode optical fiber. The unique optical properties of NSs - featuring a 40 nm gold core surrounded by silver branches of variable size and shape - allows for precise tuning of the LSPR effect. For comparison, we also explored spherical gold NPs with a 40 nm diameter to assess performance differences. Our findings, both numerical and experimental, demonstrate that the LSPR wavelength and sensitivity to surrounding refractive index can be finely tuned by adjusting the morphology of the NS branches. This is achieved by varying the silver nitrate content during their synthesis. Using the Finite Element Method-based design tool we performed simplified study cases, that led to experimental sensitivity of approximately 560 nm/RIU for an LSPR wavelength near 810 nm. As a practical demonstration, the sensor was successfully employed to detect Thiram, a common agricultural pesticide, with a wide dynamic range from 10 pM to 100 mu M and an impressive low limit of detection of 0.3 pM. Moreover, we investigated the sensor selectivity, stability and response to environmental temperature changes. This study emphasizes the simplicity, cost-effectiveness, and tunable performance of NS-based optical fiber sensors. By manipulating nanostructure morphology, we can significantly enhance sensor performance, positioning this technology as a highly promising solution for environmental monitoring, biomedical diagnostics, and chemical detection.
keywords
NANOPARTICLES; OPTIMIZATION; BIOSENSORS; NANORODS; ARRAYS; SIZE
subject category
Biotechnology & Applied Microbiology; Chemistry; Electrochemistry; Science & Technology - Other Topics; Instruments & Instrumentation
authors
Moslemi, A; Sansone, L; Esposito, F; Marques, C; Campopiano, S; Giordano, M; Iadicicco, A
our authors
Carlos Marques
Assistant ProfessorProjects
Collaboratory for Emerging Technologies, CoLab (EMERGING TECHNOLOGIES)
Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)
acknowledgements
This work was performed within the project "Monitoring of Honeybee Immunomodulation and Resilience to Stress Factors by Fiber Optic Technology" (MoBeeFO) CUP I53D23000390006 under PRIN 2022 grant financed by the European Union - Next Generation EU, Mission 4 Component 1 and Italian Ministry of University and Research. This work was developed within the scope of the projects CICECO (LA/P/0006/2020, UIDB/50011/2020 & UIDP/50011/2020) and DigiAqua (PTDC/EEI-EEE/0415/2021) , financed by national funds through the (Portuguese Science and Technology Foundation/MCTES (FCT I.P.) ) . The research was co-funded by the financial support of the European Union under the REFRESH - Research Excellence For REgion Sustainability and High-tech Industries project number CZ.10.03.01/00/22_003/0000048 via the Operational Programme Just Transition.