A new type of amperometric gas sensor, based on screen printing and lamination strategies, has been fabricated and tested. These sensors use thin film electrodes, printed on plastic substrates to form a small, low power (μW) amperometric sensor package, which uses a very small volume of electrolyte. These sensors have been demonstrated to have improved performance compared to amperometric gas sensors of conventional design, when conventional electrolytes are used. The sensors have also been demonstrated to have promising performance, compared to conventional technology, using room temperature ionic liquid electrolytes (RTILs). The printed sensors have been demonstrated successfully for monitoring of carbon monoxide (CO), ammonia (NH3).

Hydrogen peroxide (H2O2) is a key molecule in numerous physiological, industrial, and environmental processes. H2O2 is monitored using various methods like colorimetry, luminescence, fluorescence, and electrochemical methods. Here, we aim to provide a comprehensive review of solid state sensors to monitor H2O2. The review covers three categories of sensors: chemiresistive, conductometric, and field effect transistors. A brief description of the sensing mechanisms of these sensors has been provided. All three sensor types are evaluated based on the sensing parameters like sensitivity, limit of detection, measuring range and response time. We highlight those sensors which have advanced the field by using innovative materials or sensor fabrication techniques. Finally, we discuss the limitations of current solid state sensors and the future directions for research and development in this exciting area.

The behavior of amperometric gas sensors using room temperature ionic liquid electrolytes is discussed. Ionic liquid electrolytes were used to prepare amperometric gas sensors in conventional and novel, printed configurations. These sensors were demonstrated for monitoring two toxic gases: ammonia and ozone. For ammonia sensors, the response was compared to a commercial sensor. The issues surrounding sensor performance are discussed. New results are also presented for ozone and nitrogen dioxide monitoring with second generation printed sensors using ionic liquids.

We discuss here further issues in the application of room temperature ionic liquid electrolytes to printed amperometric gas sensors. The main issue addressed is design of the amperometric gas sensor, relative to selection of optimal ionic liquid electrolytes for the realization of new gas sensors with superior properties of robustness, stability, sensitivity and limit of detection. Examples are provided in the context of ammonia monitoring.

No abstract