Pyroelectric array sensor

Table I, provided yet another instrumental approach for balloon experiments intended to measure the extinction of solar radiation by stratospheric aerosol. Spectrometer 4, Table I, based on the use of a pyroelectric vidicon image device, was developed to measure the strong absorption bands of non-isonuclear molecules ( 2-5 ym range). Recently we have developed spectrometer 5, Table I, based on the use of a self-scanned solid state pyroelectric array sensor. The main advantages of this sensor, over the pyroelectric vidicon, are its improved sensitivity and reduced channel-to-channel cross-talk.

The realization of an IR matrix array sensor leading to a simple component associate for this first time a pyroelectric polymer and a silicon CQD. This component could be used in mass production infra-red cameras (for example in car industry). 

It is important that all indicated devices can function at room temperatures. This means that polymer-based sensors have low power consumption (of the order of microwatts) because no heater element is required for their operation. Properties of polymers that influence the operating parameters of sensors can be physicochemical, chemical, optical (photo- and electroluminescence, optoelectronic), redox, hydrophobic/ hydrophilic, piezoelectric/pyroelectric, and electrical (conductivity, resistivity). Moreover, the polymer itself can be modified to bind biomolecules to a biosensor (Mulchandani and Wang 1996). It is mentioned above that polymers have considerable potential for fabrication of multisensing arrays required for e-nose fabrication (Janata and Huber 1985). 

A somewhat different approach with a pyroelectric detector chip was su ested by Schreiter et al. (2006). The advantages of such a lead-zirconate-titanate-based detector array are the low heat capacity and high thermal insulation of the sensor. The surface of the sensor was coated with specific reagents to detect different chemicals. As an example, the coating with poly(methylsiloxane) was chosen to detect heptane with a detection limit of 10 ppm. With a bacterial surface layer and small Pt clusters, it was possible to study the catalytic oxidation of hydrogen in the range of 0.5-3.5 vol%. 

Figure 2 shows the set up of a multichannel gas sensor. The IR multichannel detector consists of for example a pyroelectric detector array with n detectors. The interference filter array is made up of an arrangement of filters for each of the detectors n-1 channels are used for the detection of different gas components. One channel serves as the optical reference, where no gas absorption takes place. 

An electrothermal imaging device contains an array of pyroelectrical sensor elements supported by a pillar of a semiconductor like PT [160]. 

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