Fig. 4: Performance evaluation of the hydrogen sensor hardware, including the Joule heating process.
From: Long-term reliable wireless H2 gas sensor via repeatable thermal refreshing of palladium nanowire
a Optical image of the sensor hardware. b Block diagram of the sensing hardware. c Hydrogen concentration measurement on the developed module. d Temperature profile of the Pd nanowire device through FEM simulation. e Experimented temperature distribution through thermal imaging camera during joule heating. f Changes in humidity and analog-to-digital converter (ADC) values of the hardware in a H2 concentration range of 0.1% to 1%, comparing the initial and contaminated states (1-day) g and the initial and after joule heating states. h Quantitative comparison of response time (\({{{\rm{\tau }}}}_{{res}}\)) and gas response (\({\Delta R/R}_{0}\)) with respect to before and after joule heating. i Repetitive observations of recovery with joule heating. j Long-term contamination test with thermal refreshing after 61 days of contamination. The error bars in (h) and (j) represent the standard deviations from three individual devices.
