Electrical properties of doped polypyrrole/silicon heterojunction diodes and their response to NOx gas

Conducting polymers in chemical sensors and arrays

“…Aluminium and/or gold were used as metals while PANI, P3OTH and PPY were used as CP in these diodes. Chemosensitive diodes formed by a junction of n-doped silicium and PPY or PANI were also reported and used as gas sensors [303,304].…”

Chemical Gas Sensors Based on Organic Semiconductor Polypyrrole

“…It is assumed that, due to the highly ordered layered structure and the relatively high packing density of MPcTS-doped PPy, the vapor diffusion in and out of the layer is very slow, resulting in a long response time. In contrast, PPy samples doped with smaller inorganic anions such as ClO 4 and BF 4 exhibit an amorphous structure and a lower density. They show faster response times in the range of 1 to 3 min.…”

“…42 Nevertheless, MIS field effect transistors, Schottky, and heterojunction diodes can be used as chemical sensors, in which the conducting polymer acts as both the active semiconductor and the chemical-sensitive transducer element of the sensor structure. [2][3][4][5][6] …”

“…The combination of the properties make PPy particularly attractive for applications in intelligent gas sensors, in which the organic semiconductor PPy acts as both the active semiconductor and the chemical sensitive transducer element of the sensor structure. [2][3][4][5][6] However, it brings about a self-limitation of their use. Due to its sensitivity to various gases and vapors the selectivity is low, which is the most serious problem in the use of PPy for gas or vapor detection.…”

Fiber-Optic Chemical Sensor for Detection of NO2Using Poly (3-Octylthiophene)

“…Organic semiconductors such as polypyrrole and polythiophen have been proposed as sensitive materials for NO 2 gas detection and used in the design of NO 2 sensors. It has been reported that polythiophene is highly sensitive to NO 2 , poorly sensitive to H 2 S, and insensitive to different gases such as CH 4 , C 3 H 8 , C 3 H 6 , CO, and SO 2 [10,11]. In those cases, the sensor was based on the conductive changes produced by the adsorption of NO 2 at different concentrations.…”