Hydrogen sensor based on planar polymer Bragg grating coated with Pd/Ni composite film

As one of the cleanest energy sources in the 21st century, the development of hydrogen energy has attracted the attention of all countries in the world, so the monitoring of hydrogen leakage has become a current research focus. This study demonstrates a novel hydrogen sensor that combines a planar polymer grating with a Pd/Ni hydrogen-sensitive material that takes advantage of the hydrogen-absorbing expansion properties of Pd to cause the central wavelength drift of Planar Polymer Bragg Grating (PPBG) by strain transformation. The experimental results show when the hydrogen concentration is 0.3%, 0.6% and 1%, the wavelength shift of the sensor is 50 pm, 85 pm and 110 pm respectively, and the response time is approximately 30 seconds. This hydrogen sensor has the advantages of high sensitivity, low cost and compact structure, leading to great potential in industrial applications.