Proposal and Evaluation of Dissolved Oxygen Image Sensor Using Iridium Oxide as Sensing Membrane

In this study, an iridium oxide (IrO
x
) film was deposited on a potentiometric array sensor with a pixel pitch of 23.55 μm, and an imaging device that can visualize dissolved oxygen (DO) in two dimensions was successfully fabricated for the first time. The output of the sensor showed a linear response in the DO concentration range of approximately 8 ppm to 30 ppm, with a response sensitivity of 27 mV/log[O
2
]ppm. The response was reversible when the DO concentration was increased and decreased, confirming that the IrO
x
thin film functions as a DO-detection-sensitive membrane. We found the possibility of real-time visualization of oxygen consumption in small areas, such as blood and cells. In this study, the redox response of the IrO
x
film was linked to changes in DO concentration, and the response mechanism of the sensor was discussed.