Gas Sensor with Reduced Humidity Response Based on Metal Oxide Nanoparticles Synthesized by Spark Discharge

Abstract

The most part of gas sensors based on tin dioxide semiconductor sensing material are fabricated by using sol-gel synthesis of SnO 2 . This process leads to the formation of highly sensitive sensing material; however, it forms hydroxyl groups on the surface of tin dioxide, leading, in turn, to strong parasitic sensitivity of the sensor to changing humidity. This sensitivity can be reduced by calcination of sensing material, but this treatment also reduces considerably the total response of the sensor to target gases. In this work, we investigated the possibility of the dry synthesis of tin dioxide nanoparticles by gas phase spark discharge. After the annealing at 610 o C, the specific area of the material synthesized by spark discharge was about 40 m 2 /g. The sensing layer resistance of the sensor decreases by only 20%, when relative humidity of a carrier air increases from 40 to 100%. At the same time, the hydrogen response of the sensor remains the same as for the material prepared by sol-gel synthesis, that is factor of 8 at 100 ppm concentration of H 2 . Very important property of the sensor is short response time of ~ 1-2 s to both hydrogen and humidity.

Aerosol Jet Printing of Silver Lines with A High Aspect Ratio on A Heated Silicon Substrate

“…Among the existing printing methods, aerosol jet printing is the most promising technology because it allows the formation of functional elements with a minimum lateral size of up to 10 microns [7][8][9] both on flat and curved substrates [10,11]. This technology has been applied for the manufacture of transistors [12], sensors [13][14][15], solar cells [16], microheaters [17], microantennas [18,19] and interconnects [20]. Previous studies of this technology relied mainly on the formation of thin-film microstructures due to the need for the manufacture of planar electronic devices.…”