Ultra-sensitive hydrogen gas sensing using DNA-templated palladium nanowires

This paper focuses on an ultra-sensitive H₂ sensor fabricated using a time and cost-effective method. The sensor is comprised of Pd nanowires fabricated using λ-DNA templates. The morphology and the electrical characterisation of the metalized DNA nanowires (diameter = 5-45nm) were investigated by AFM and conductive AFM (cAFM). The conductivity of a single Pd-DNA nanowire, 127 Scm^-1 was substantially lower than that of bulk Pd (9.5×10⁴ Scm^-1). However, the sensor shows high sensitivity towards hydrogen evaluated by recording the change in the resistance on exposure to cycles of different concentrations of H₂ in N₂ flow at 330K. The sensor showed a reversible response to H₂ concentrations between 2300 - 12500 ppm and a response time of ~85 s. These results indicate that using DNA as a template is a promising method for the fabrication of low cost and rapid response sensors.