Amplifying Fibre Optic Sensor Signals with Graphene Oxide-Silver Nanostars

• Published in: Journal of Mechanical Engineering
• Main Author: Roslan A.H.; Makhsin S.R.; Rani R.A.; Siddique B.
• Format: Article
• Language: English
• Published: UiTM Press 2024
• Online Access: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85202685459&doi=10.24191%2fjmeche.v21i3.27359&partnerID=40&md5=0f09039fd30753bd9b2ed07564eca8ee

This work presents a straightforward yet impactful method to enhance optical fibre sensor signals by integrating silver nanostars (AgNS) with graphene oxide (GO-AgNS) as a sensing material. AgNS were synthesized successfully via a one-step chemical reduction method using hydroxylamine as a reducing agent. The concentration of hydroxylamine was varied (7.2, 3.6, 1.8, and 0.9) x 10−4 %v/v to optimize AgNS formation, with the longest spike of the nanostar observed at lower hydroxylamine concentrations, as confirmed by transmission electron microscopy (TEM). UV-visible measurements revealed the highest peak absorption for AgNS synthesized using 0.9 x 10−4 %v/v hydroxylamine, 0.05 M sodium hydroxide, 0.8 mM silver nitrate, and 0.045 M sodium citrate, with an average length of 352.62 ± 59.72 nm measured from TEM images. GO was synthesized via a modified Hummer’s method and mixed with AgNS at varying ratios (1:5, 1:10, 1:15, and 1:20) to form GO-AgNS coatings for the fibre optic probe. The GO-AgNS coating at a ratio of 1:5 exhibited the highest light absorption intensity, enhancing optical signal by 218% compared to GO-coated and 174% compared to AgNS-coated fibre optic sensors. These findings demonstrate that embedding AgNS onto the GO matrix structure as a sensing material significantly improves sensor performance, suggesting promising applications for super-sensitive, cost-effective, and rapid detection in fibre optic-based sensors. © 2024 College of Engineering, Universiti Teknologi MARA (UiTM), Malaysia. https://doi.org/10.24191/jmeche.v21i3.27359