Ammonia Sensing by PANI-DBSA Based Gas Sensor Exploiting Kelvin Probe Technique

Anju Yadav,Ajay Agarwal,Pankaj B Agarwal,Parveen Saini

doi:10.1155/2015/842536

Abstract

Dodecyl benzene sulfonic acid (DBSA) doped polyaniline (PANI-DBSA) has been synthesized by chemical oxidative polymerization of aniline monomer in the presence of DBSA. The UV-visible spectroscopy and X-ray diffraction measurements confirm the formation of PANI and its doping by DBSA. SEM images show the formation of submicron size rod shaped PANI particles. A vibrating capacitor based ammonia gas sensor was prepared by spin coating PANI-DBSA film over copper (Cu) substrate. The sensor exploited Kelvin probe technique to monitor contact potential difference between PANI and Cu as a function of time and ammonia concentration. Upon exposure to 30 ppm ammonia, the sensor displays response time of 329 s, recovery time of 3600 s, and sensitivity value of 1.54 along with good repeatability.

Highlights

Ammonia has vast applicability like use in agricultural sector, chemical industries, medicinal fields, refrigeration systems, and so forth [1,2,3,4]
A sensing system is formed by deposition of a layer of PANI-dodecyl benzene sulfonic acid (DBSA) over copper (Cu) substrate and the time dependent change in contact potential difference (CPD) between PANI and Cu is measured by Kelvin Probe for exposure to a given ammonia concentration
The relative prominence of 25∘ peak confirms the existence of PANI in its highly doped emeraldine salt (ES) form, which is expected to show good sensitivity towards basic gases like ammonia. 2.2

Summary

Introduction

Ammonia has vast applicability like use in agricultural sector, chemical industries, medicinal fields, refrigeration systems, and so forth [1,2,3,4]. Metal oxides based ammonia gas sensors have been developed with fast response and high sensitivity [8, 9] They have disadvantages like complex fabrication steps, high power consumption, high temperature operation, and so forth [7, 10, 11]. A sensing system is formed by deposition of a layer of PANI-DBSA over copper (Cu) substrate and the time dependent change in CPD between PANI and Cu is measured by Kelvin Probe for exposure to a given ammonia concentration. Cu substrate were recorded after every second using a data acquisition system

Results and Discussions

E VAC WF1

Conclusion