Microfabricated solid-state dissolved oxygen sensor

This paper describes the design, fabrication and testing of a microfabricated oxygen concentration sensor consisting of a microfabricated thin-film electrode matrix overlaid with a solid-state proton conductive matrix (PCM) and encapsulated in a bio-inert polytetrafluoroethelene (PTFE) film. Through cyclic voltammetry (CV) and voltage step (VS) measurements, the device was shown to have a linear response with respect to dissolved oxygen concentration over a range from 0 to 601 μM (0–200 atm% O2). The diffusion constant of the PCM was measured to be D1=1.7×10−10 m2/s (±2.7×10−11 m2/s, n=40), which translates to a response time constant of τ=0.7 s (±0.11 s, n=40). These results were consistent with those predicted by basic electrochemistry.