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Room Temperature Hydrogen Sensing Based on Tapered Optical Fiber Coated with Polyaniline (PANI)
1, 2 , 3, 4 , 5 , 6 , 7 , 4 , * 4
1  Computer Center, University of Fallujah, Al-Fallujah, Iraq.
2  Department of Medical Instrumentations Techniques Engineering , AL-Rasheed University College, Baghdad, Iraq.
3  Department of Computer Engineering, Federal Polytechnic Mubi, Adamawa State, Nigeria.
4  Wireless and Photonics Network Research Center, Faculty of Engineering, University Putra Malaysia,43000 UPM Serdang, Selangor, Malaysia
5  Institute of Advanced Technology (ITMA), Universiti Putra Malaysia, 43400, Selangor Darul Ehsan, Malaysia
6  Department of Physics, Faculty of Science, University Putra Malaysia, 43400, Serdang, Selangor, Malaysia
7  Department of Electrical, Electronic and System Engineering, Faculty of Engineering and Built Environment, University Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia
Academic Editor: Run Zhang


This work demonstrates a hydrogen (H2) sensor composed of a tapered optical fiber coated with polyaniline (PANI) nanofibers that operates at room temperature. A transducing platform was fabricated using multimode optical fiber (MMF) with cladding and core diameters of 125 µm and 62.5 µm, respectively. To enhance the light evanescent field surrounding the fiber, it was tapered from the diameter of 125 µm to a waist diameter of 20 µm, a waist-length of 10 mm and coated with PANI using the drop-casting technique. To establish the PANI’s properties, various characterization techniques were applied, such as Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-Ray (EDX), X-Ray Diffraction (XRD) and Atomic Force Microscopy (AFM). The optical properties of PANI layer changes when it is exposed to H2, leading to a change in the light absorbance. The fabricated sensor was tested by exposing it to H2 at different concentrations of 0.125% to 1.00%. In this case, the sensitivity, response and recovery times were 15.928/vol%, 110 s and 160 s, respectively. Owing to its room temperature operation, the developed hydrogen sensor is promising for environmental and industrial applications.

Keywords: Hydrogen (H₂), Tapered optical fiber, Polyaniline (PANI), Drop-casting technique