Penerapan Metode Imprinting dan Doping Dye pada LapisanTipis Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)untuk Meningkatkan Selektivitas dan SensitivitasSensor Gas Amoniak

Application of imprinting method and doping dye to Poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) thin film to improve the selectivity and sensitivity of the sensor to ammonia gas has been investigated. Imprinting of ammonia gas was performed by injecting ammonia gas into the spin-coating chamber during deposition process of PEDOT:PSS thin film, while doping dye was done by mixing pH indicator dye of bromocresol green (BCG) and PEDOT:PSS solution. PEDOT:PSS thin films were fabricated by using spin-coating technique. Electrical response of the sensor was measured by using calibrated electrometer and digital multimeter, while optical response of the sensor was measured by using UV-Vis spectrophotometer and a system which consists of laser diode, photodiode, and data acquisition system which is connected to computer. The results of research based on electrical measurement show that currentvoltage characteristic tends to be linear. It means that the contact between gold electrodes and PEDOT:PSS thin film is an ohmic-contact. Application of imprinting method to PEDOT:PSS thin film can increase selectivity of the sensor to ammonia gas. The improvement of sensor selectivity is about 2-folds to acetone gaseous and 10-folds to methanol gaseous which is compared with the selectivity of the sensor without imprinting. The sensitivity of imprinted sensor to ammonia gas is about 0.02%/ppm with limit of detection is about 37.5 ppm. The sensor has a good repeatability and short response and recovery time, e.i. 10 seconds and 15 seconds respectively. On the other hand, the results of optical measurement show that doping dye of BCG to PEDOT:PSS can improve the sensor sensitivity with about 2-folds compared with sensitivity of the imprinted sensor. Sensitivity of the sensor is about 0.05% per ppm and detection limit is about 12 ppm. This sensor also has a good repeatability with short response and recovery time, e.i. 1 second and 15 seconds respectively. Therefore, application of imprinting method and doping dye to PEDOT:PSS are more effective to increase the selectivity and sensitivity of the sensor to ammonia gas.