Fast response solid electrolyte oxygen sensors with porous thin film electrodes

Area of Science:

• Atmospheric Science
• Sensor Technology
• Materials Science

Background:

• Accurate measurement of atmospheric atomic oxygen is crucial for understanding upper atmospheric dynamics.
• Conventional flux probe experiment (FIPEX) sensors have limitations in response time.
• Sounding rocket missions require robust sensors for extreme altitude measurements.

Purpose of the Study:

• To introduce a novel solid electrolyte sensor, eFIPEX, with enhanced response times.
• To detail the manufacturing process and characterization of the eFIPEX sensor.
• To evaluate the performance of eFIPEX sensors in atmospheric atomic oxygen measurements.

Main Methods:

• Developed a new electrode fabrication technique combining platinum film deposition via a polyol process and electrochemical etching.
• Utilized gold plating for selective atomic oxygen detection.
• Characterized electrode geometry and composition using optical microscopy, electron microscopy, and energy dispersive x-ray spectroscopy.
• Compared eFIPEX sensor performance against conventional FIPEX sensors during a sounding rocket flight.

Main Results:

• Significantly improved response times were achieved with the eFIPEX sensor.
• Pore formation in the platinum film down to the substrate was identified as the cause of faster response.
• eFIPEX sensors demonstrated superior performance compared to conventional FIPEX sensors on the PMWE-2 sounding rocket flight.
• Electrodes with thicknesses ranging from 200 nm to 1.5 μm were successfully manufactured.

Conclusions:

• The novel eFIPEX sensor offers a significant advancement in measuring atmospheric atomic oxygen.
• The improved transient behavior and easier fabrication make eFIPEX suitable for future atmospheric research missions.
• eFIPEX represents a promising new tool for atmospheric atomic oxygen concentration measurements up to 250 km altitude.