A fiber-optic evanescent wave O2 sensor based on Ru(II)-doped fluorinated ORMOSILs.

Area of Science:

• Materials Science
• Optical Sensors
• Chemical Sensing

Background:

• Fiber-optic sensors offer advantages in remote and harsh environment sensing.
• Oxygen detection is crucial in various industrial and environmental applications.
• Organically modified silicates (ORMOSILs) provide a versatile matrix for optical sensor development.

Purpose of the Study:

• To develop a novel fiber-optic evanescent wave sensor (FOEWS) for oxygen (O(2)) detection.
• To utilize [Ru(bpy)(3)](2+)-doped hybrid fluorinated ORMOSILs for enhanced sensing performance.
• To investigate the sensor's sensitivity, response time, and limit of detection.

Main Methods:

• Fabrication of the sensing element via dip-coating an optical fiber with [Ru(bpy)(3)](2+)-doped hybrid fluorinated ORMOSILs.
• Formulation of ORMOSILs using n-propyltrimethoxysilane (n-propyl-TriMOS) and 3,3,3-trifluoropropyltrimethoxysilane (TFP-TriMOS).
• Characterization of spectroscopic properties using FTIR and UV-VIS absorption measurements.
• Evaluation of sensor performance based on fluorescence quenching by O(2).

Main Results:

• The developed FOEWS demonstrated efficient O(2) detection through fluorescence quenching of [Ru(bpy)(3)](2+).
• Hybrid fluorinated ORMOSILs enhanced surface hydrophobicity, leading to increased quenching response.
• The sensor achieved a sensitivity of 7.5 (I(N2)/I(O2)), a limit of detection (L.O.D.) of 0.01% (3sigma), and a response time of approximately 1 second.
• Successful oxygen monitoring was achieved using a blue LED light source and a miniature PMT detector.

Conclusions:

• A novel, cost-effective, and easy-to-fabricate FOEWS for O(2) detection was successfully developed.
• The use of hybrid fluorinated ORMOSILs significantly improved sensor performance, particularly sensitivity and response.
• The sensor exhibits suitable characteristics for practical oxygen monitoring applications.