Selectivity improvement of gas sensor based on poly(3,4-ethylenedioxythiophene):Poly(styrenesulfonate) Thin Film by using imprinting method

Selectivity improment of gas sensor based on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) thin film to ammonia gas has been studied. The PDOT:PSS thin films were deposited on glass and FR4 substrates by using a spin-coating technique. PEDOT:PSS solution was spread on the substrate followed by spinning at fixed rate. Then, the imprinting process of gas sensor was performed by injecting ammonia gas into the spin-coating chamber. Finally, the gas sensor was dried on a controllable hot plate. Current-voltage characteristics of the films were measured by using calibrated electrometer. The results show that by imprinting of ammonia gas to the film affects the electrical conductivity of the film. It is also shown that the electron transport in the PEDOT:PSS thin film tends to be ohmic-contact. When the imprinted sensor is exposed in ammonia gas, we obtained that the sensor has short response and recovery time, a good repeatability (reversible), and higher sensitivity to ammonia gas. To this end, we found that ammonia imprinting on the surface of PDOT:PSS thin film can improve the selectivity of the sensor to ammonia gas. It indicates that our method can be used for fabricating the sensor which has a single selectivity