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Journal of Nanotechnology
Volume 2014 (2014), Article ID 864274, 5 pages
Research Article

Sensitivity Improvement of Ammonia Gas Sensor Based on Poly(3,4-ethylenedioxythiophene):Poly(styrenesulfonate) by Employing Doping of Bromocresol Green

1Physics Department, Gadjah Mada University, Sekip Utara BLS.21, Yogyakarta 55281, Indonesia
2Physics Department, Haluoleo University, Jl. HEA Mokodompit, Kampus Hijau Bumi Tridharma Anduonohu, Kendari 93232, Indonesia
3Chemistry Department, Gadjah Mada University, Sekip Utara BLS.21, Yogyakarta 55281, Indonesia
4Physics Department, Lampung University, Jl. Prof. Dr. Sumantri Brojonegoro No. 1, Bandar Lampung 35145, Indonesia

Received 31 July 2013; Revised 15 November 2013; Accepted 1 December 2013; Published 22 January 2014

Academic Editor: Yoke Khin Yap

Copyright © 2014 La Aba et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The aim of this research is to improve the sensitivity of ammonia gas sensor (hereafter referred to as sensor) based on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) by employing the doping dye of bromocresol green (BCG). The doping process was carried out by mixing the BCG and the PEDOT:PSS in a solution with an optimum ratio of 1 : 1 in volume. The sensor was fabricated by using spin-coating technique followed by annealing process. For comparison, the BCG thin film and the PEDOT:PSS thin film were also deposited with the same method on glass substrates. For optical characterization, a red-light laser diode with a 650 nm wavelength was used as light source. Under illumination with the laser diode, the bare glass substrate and BCG film showed no absorption. The sensor exhibited linear response to ammonia gas for the range of 200 ppm to 800 ppm. It increased the sensitivity of sensor based on PEDOT:PSS with BCG doping being about twofold higher compared to that of without BCG doping. Furthermore, the response time and the recovery time of the sensor were found very fast. It suggests that the optical sensor based on BCG-doped PEDOT:PSS is promising for application as ammonia gas sensor.