Sensors transistors

In this chapter, we intend to revise the most recent contributions to the aforementioned aspects of Pc research. We will describe how the versatile chemistry of Pcs makes possible the preparation of monofunctionalized macrocycles, mainly aimed at preparing multicomponent systems through reaction with other electroactive moieties. The controlled organization of Pcs in solution and the incorporation of these chromophores into macromolecular structures, as well as the preparation of mono-, bi-, and three-dimensional nanostructures, will be the object of study. Finally, some examples of Pc-based devices (solar cells, sensors, transistors, etc.) will also be given as an example of the real applicability of these molecules. 

Nilsson, D. et al.. An all-organic sensor-transistor based on a novel electrochemical transducer concept printed electrochemical sensors on paper. Sens. Actuators B, 86, 193, 2002. 

This size reduction is analogous to a continuous decrease in the dimensions of species accessible for studies and applications. Not only that small is beautifiil, but also it enforces progress and provides a new dimension to science and technology. Chemists are finally able to work with single molecule and atoms, yet not billions of them at a time. Nano has become a buzzword of the new century. New nano journals and nano letters and nano webpages have been emerging. We are constantly reading about nano wires, sensors, transistors, and nanocomputers. 

Antistatic equipment, immersion heating systems, sensors, transistors or reversible batteries, electronic devices, medical application, drug release [13, 57-59]. 

F. Yokosuka and T. Ttamiia. Acceleration sensor. Transistor TechnoL, No. 11. p. 475 (1986). L Sco. Impact sensor using piezoelectric polymer. 142ih Report on organic materials for informatioo sdeace, 1984, p. 125 (in Japanese). 

The rate and the degree of reaction of an electrically conductive polymer in repeated redox reaction are important factors in application of the polymer. The fast response of the polymer to an external stimulation may find uses in a sensor or a display. The reaction rate must depend on the mobility of ions in the polymer toward the reactive sites under an applied potential. The degree of the reaction in the cycled oxidation-reduction process predicts applicability of the electrically conductive materials in battery, sensor, transistor, solar cells, etc(6,7). 

Lead sulfide is used in photoconductive cells, infrared detectors, transistors, humidity sensors in rockets, catalysts for removing mercaptans from petroleum distillates, mirror coatings to limit reflectivity, high temperature solid-film lubricants, and in blue lead pigments (82). 

Fig. 4. Some electronic device applications using amorphous silicon (a) solar cell, (b) thin-fiLm transistor, (c) image sensor, and (d) nuclear particle detector.

ORGANIC SEMICONDUCTOR THIN-FILM TRANSISTOR SENSORS... 

Novel glycerol and formaldehyde selective sensors based on pEI-Sensitive Field Effect Transistors as transducers and Glycerol Dehydrogenase and Formaldehyde Dehydrogenase as biorecognition elements have been developed. The main analytical parameters of the sensors have been investigated and will be discussed. 

The use of arachidic acid and different amphiphilic calixarenes for modifying of field effect transistor sensors and determination of some volatile organic contaminants will be considered. 

Instruments based on the contact principle can further be divided into two classes mechanical thermometers and electrical thermometers. Mechanical thermometers are based on the thermal expansion of a gas, a liquid, or a solid material. They are simple, robust, and do not normally require power to operate. Electrical resistance thermometers utilize the connection between the electrical resistance and the sensor temperature. Thermocouples are based on the phenomenon, where a temperature-dependent voltage is created in a circuit of two different metals. Semiconductor thermometers have a diode or transistor probe, or a more advanced integrated circuit, where the voltage of the semiconductor junctions is temperature dependent. All electrical meters are easy to incorporate with modern data acquisition systems. A summary of contact thermometer properties is shown in Table 12.3. 

Semiconductor High-power transistors High-power microwave Photovoltaic elements Field-effect transistors UV sensors... 

In recent years further concepts have been developed for the construction of polymer-based diodes, requiring either two conjugated polymers (PA and poly(A-methyl-pyrrole) 2 > or poly(A-methylpyrrole in a p-type silicon wafer solid-state field-effect transistor By modifying the transistor switching, these electronic devices can also be employed as pH-sensitive chemical sensors or as hydrogen or oxygen sensors 221) in aqueous solutions. Recently a PPy alcohol sensor has also been reported 222). 

Apart from transistor-like devices, single-electron junctions can also be useful for sensor applications. The simplest one might be the monitoring of H2S. Since the formation of CdS nanogranules takes place when an initial cadmium arachidate layer is exposed to this gas, we can expect the appearance of single-electron conductivity only when it is present in the atmosphere. 

There is no doubt that metallic nanoparticles that have defined sizes and shapes will become key components of a number of novel, highly sophisticated products, the prototypes of which are currently emerging from the industrial R D departments. The outlook is promising for the industrial production of defined 1.4nm metal clusters for use as single electron switches or transistors, for the cost-effective fabrication of ultrapure metallic nanomaterials needed for dye solar cells or sensors, and for the reproducible production of (particularly) efficient and durable... 

The ISFET is an electrochemical sensor based on a modification of the metal oxide semiconductor field effect transistor (MOSFET). The metal gate of the MOSFET is replaced by a reference electrode and the gate insulator is exposed to the analyte solution or is coated with an ion-selective membrane as illustrated in Fig. 

Janata, J. Chemically Sensitive Field Effect Transistors, in Solid State Chemical Sensors (Janata, J., Huber, R. J., eds.) New York Academic Press 1985, p. 65... 

Kolesar ES, Wiseman JM. 1991. Selective detection of nitrogen-dioxide and diisopropyl methylphosphonate with an interdigitated gate electrode field-effect transistor (IGEFET). Sensors and Actuators B - Chemical 5(l-4) 37-46. 

Comparable is the CHEMFET (Chemical Field Effect Transistor), a chemical sensor on a FET, e.g., for H , Na, K and Ca2+ in blood, four CHEMFETs had been mounted on one plate [Clin. Chem., 30 (1984) 1361. 

Figure 7. Scheme of a field effect transistor sensor. 

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