All-Optical Hydrogen Sensor: The development of harsh environment compatible chemical sensors with sufficient reliability, sensitivity and selectivity requires the tailored design of both the composition and microstructure of the active sensing layer. These efforts have led to the development of an intrinsically safe all-optical hydrogen sensor based on monitoring the optical properties of thin palladium alloy films as a function of hydrogen concentration. For this project the tailored design process optimized both the alloying element and its composition along with the microstructure of the resulting film, all of which were subsequently correlated with the resulting sensing properties. Our oldest films were deposited in December 2002 and continue to operate within 5% of their corresponding calibration curves and have response characteristics that are comparable or better than industrially available electronic based hydrogen sensors.

Z. Zhao, M. A. Carpenter, D. Welch, H. Xia
All-Optical Hydrogen Sensor Based on a High Alloy Content Palladium Thin Film
Sensors and Actuators B, 113 , 532 (2006)

Z. Zhao, M. A. Carpenter
Annealing Enhanced Hydrogen Absorption in Nanocrystalline Pd/Au Sensing Films
Journal of Applied Physics, 97 , 124301 (2005).

Z. Zhao, Y. Sevryugina, M. A. Carpenter, D. Welch, H. Xia
All-Optical Hydrogen Sensing Materials Based on Tailored Palladium Alloy Thin Films
Analytical Chemistry, 76 , 6321 (2004)