Bimetallic nanodisk-based fiber-optic plasmonic nanoprobe for gas detection.

In this study, gold-palladium bimetallic nanodisks were patterned on optical fibers via nanosphere lithography and chemical growth. The conditions related to the density of the structures, concentration of the growth solution, and growth time were modified. The structural features of nanodisks with a large surface area and enhancement of plasmonic efficiency owing to the palladium shell resulted in a high refractive index sensitivity. Additionally, based on palladium's sensitivity to hydrogen, hydrogen sensing was performed at various concentrations with a detection limit of 0.125 % and signal-to-noise ratio of 24.2 dB. The response time and hysteresis showed a good performance relative to those of other hydrogen sensors. The high throughput of the nanosphere lithography and simple seed-mediated growth make this system a cost-effective fiber-optic plasmonic nanoprobe. Based on these investigations, the optical fiber-based plasmonic nanoprobe can be actively applied to detect dangerous environments using remote sensing for safety management in the clean energy era.