Research Of Fiber Surface Plasmon Resonance Hydrogen Sensor Base On Pd And Au Nanoparticles

Hydrogen is an important energy and industrial raw material. But for its special property including flammability, diffusivity and explosibility, it's also great crucial to explore some reliable and accurate technique which can detect hydrogen during application. The optical fiber Surface Plasmon Resonance hydrogen sensor based on Pd and Au nanoparticles has the advantages of high sensitivity, short response time and strong adaptability in complex environment for which has great prospects for research and application.In this paper, a hydrogen sensor with the tilted grating modified by Pd and Au film is studied. The main work is as follows:1. The optical properties of Au and Pd nanoparticles were simulated, and the optical characteristic of Au and Pd nanoparticles were simulated by Finite Difference Time Domain(FDTD) method. The Surface Plasmon Resonance (SPR) phenomenon of Au and Pd films on the substrate surface is studied by programming with the matched matrix theory. The thickness of this film is optimized; the performance parameters including responding concentration,responding and recovery time of Pd thin film hydrogen sensors were simulated by hydrogen diffusion model.2. Au and Pd nanoparticles were prepared by chemical liquid reduction method. Spherical Au nanoparticles which particle sizes are about 4nm and 20nm were synthesized by sodium borohydride reduction method and sodium citrate reduction method respectively. Pd nanoparticles with size of 4.7nm and good monodisperse were prepared by reduction of ascorbic acid; transmission electron microscopy (TEM) results show that the size distribution is uniform; the ultraviolet-visible(UV-vis) spectra analysis was applied to nanoparticles sol solution prepared under different reaction condition; the reaction process of reduce Au nanoparticles with sodium citrate was studied by UV-vis spectrometer; the reduce reaction of Pd nanoparticles in Au nanoparticles solution was studied as well.3.The controllable growth of Au and Pd nano films on quartz substrates was achieved by molecular self assembly (SAMs) and electroless plating technology. The work mentioned above included that using coupling agent (3-Aminopropyl)trimethoxysilane (APTMS) to self-assemble APTMS molecular film on the surface of hydroxylation quartz substrate, using electrostatic force to adsorb Au nanoparticles and preparing Au and Pd nano films by electroless plating method; TFBG spectrum was used to monitor the growth of Au nanoparticle films, the thickness of Au film was measured and calibrated by atomic force microscopy(AFM); The thickness of Pd film was measured by step profiler.4. Optical fiber hydrogen sensors with Pd thin films and Pd/Au thin film were prepared by electroless plating respectively, and their hydrogen sensing properties were also investigated. Under the condition of hydrogen concentration of 4%, the average wavelength shift is 45.4pm, the average response time is 22.6s and the average recovery time is 42.2s, for the sensor with Pd thin film. The Pd/Au thin film hydrogen sensor has a well linear response under the condition of hydrogen concentration of 1%-4%. the average peak to peak value of light intensity change is 0.005dB as the hydrogen concentration change in every 1%, the average response time is 16s and the average recovery time is about 40s.