Highly sensitive isoprene gas sensor using Au-loaded pyramid-shaped ZnO particles

Highly sensitive sensors to detect small amounts of gases are expected to be used for monitoring air quality and analyzing breath for medical diagnosis. We report a highly sensitive isoprene gas sensor using Au-loaded pyramid-shaped ZnO particles. The pyramid-shaped ZnO particles with (0001) base and {10 11} six side surfaces were synthesized solvothermally. Loading of 0.5 % Au nanoparticles successfully increased the sensor response. The response value (the resistivity ratio in air and isoprene gas) to 50 ppb isoprene gas was 42 at 350 degrees C in dry air, which is remarkably higher than that of previously reported sensors of metal-oxide semiconductors. Under 80 % relative humidity, the response value to 50 ppb was 4.8. The isoprene concentration dependence of the sensor response implied that 10 ppb can be detected with a response value of 1.4 and that diagnosis of liver diseases and sleep state is possible. Enhanced selectivity compared to acetone, ethanol and hydrogen was confirmed in Au-doped samples.

Automated summary

A highly sensitive isoprene gas sensor using Au-loaded pyramid-shaped ZnO particles was reported, with a remarkable response value of 42 to 50 ppb isoprene gas in dry air at 350 degrees C, and 4.8 under 80% relative humidity. The sensor shows enhanced selectivity compared to acetone, ethanol, and hydrogen, and can detect as low as 10 ppb isoprene concentration, making it possible for diagnosis of liver diseases and sleep state.