MDPI – Sensors
JAVIER GOICOECHEA; PEDRO J. RIVERO; SAMUEL SADA; FRANCISCO J. ARREGUI
Intensity-based optical fiber sensors are one of the most studied sensor approaches thanks to their simplicity and low cost. Nevertheless, their main issue is their lack of robustness since any light source fluctuation, or unexpected optical setup variation is directly transferred to the output signal, which, significantly reduces their reliability. In this work, a simple and robust hydrogen peroxide (H2O2) optical fiber sensor is proposed based on the Localized Surface Plasmon Resonance (LSPR) sensitivity of silver and gold metallic nanoparticles. The precise and robust detection of H2O2 concentrations in the ppm range is very interesting for the scientific community, as it is a pathological precursor in a wide variety of damage mechanisms where its presence can be used to diagnose important diseases such as Parkinson’s disease, diabetes, asthma, or even Alzheimer’s disease). In this work, the sensing principle is based the oxidation of the silver nanoparticles due the action of the hydrogen peroxide, and consequently the reduction of the efficiency of the plasmonic coupling. At the same time, gold nanoparticles show a high chemical stability, and therefore provide a stable LSPR absorption band. This provides a stable real-time reference that can be extracted from the spectral response of the optical fiber sensor, giving a reliable reading of the hydrogen peroxide concentration.
Link to source: https://www.mdpi.com/1424-8220/19/18/3872/htm
Fabrication of the Layer-by-Layer Films
…The resultant LbL coatings onto the optical fiber core are denoted as the sensitive region and all the LbL coatings have been fabricated by using a 3-axis Cartesian robot from Nadetech Innovations S.L. The LbL coatings show a good long-term stability and no oxidation have been observed at room conditions.