A printed, non-flexing sensor for electrochemical gas sensing

Sidebar to “Printable/flexible sensors: valuable additions to the designer’s toolkit”

Hayward, CA-based Spec Sensors has been developing screen-printed electrochemical gas sensors since receiving an NSF Small Business Innovative Research Phase One award in 2009. Their current product line, in volume production since early 2014, includes sensors that measure CO, as well as O3, H2S, NO2, SO2, NO and alcohol. Their sensor (fig. S1) is constructed with a base layer of plastic, a conductive-ink-printed gas sensitive layer, and a laminated plastic top layer. Currently, the sensor is provided in a 15 x 15 x 3.5 mm format; a 10 x 10 x 2.5-mm version is expected by the end of 2015.

Fig. S1: A Spec Sensors'  screen-printed electrochemical gas sensor is constructed with a base layer of plastic, a conductive-ink-printed gas sensitive layer, and a laminated plastic top layer.

Company founder Joe Stetter explains that, “Our decision to develop printable/flexible sensors was greatly influenced by the printed electronics industry. However, we needed to needed to create much of the necessary design and manufacturing infrastructure in-house since we did not have the luxury of using a production ‘foundry’ similar to what exists in the MEMS industry. This meant that we needed to develop everything including the analytical models, materials, inks and process development. Additionally, there were no standards or roadmaps to help guide the process.”

The result of these efforts are P/F gas sensors that meet or exceed the performance specifications of 3-D approaches while providing lower cost, smaller size, and lower power consumption — key characteristics for wearables and the consumer market, especially in environmental-monitoring applications. Current applications include residential and commercial indoor/outdoor air quality monitoring for CO and NO2, and breathe monitoring for alcohol consumption.