D3.2 - CO2 Sensors Based on Workfunction Readout Using Floating Gate FET Devices with Polysiloxanes Sensing Layers

The reliable detection of CO2 is a key for demand controlled ventilation (DCV) in buildings, which allows energy savings up to 30%. Presently, optical detection methods are only in use for a small percentage of building ventilation systems due to the relatively high cost of these sensing systems. A reliable low cost CO2 sensor would allow for widespread use of DCV. In the past, various transducer principles have been used for CO2 detection and a number of sensitive materials have been investigated including organically modified silicates [1], also called siloxanes. Due to their ability to form an acid base reaction with the molecule CO2, materials using primary amino groups are particularly suitable for the detection of CO2. This has been verified using heteropolysiloxanes in mass sensitive [1] and capacitive sensors [2]. Another recent approach makes use of the workfunction readout of these materials, where CO2 detection at room temperature was demonstrated using a labscale Kelvin Probe setup [3]. The underlying detection mechanism has been carefully examined by Stegmeier et al [4].