Chemically functionalized graphene oxide thin films for selective ammonia Gas sensing

Abstract

In this work graphene oxide has been functionalized using Para chloro benzoic acid (PCBA). Three different concentrations of PCBA were used for functionalization on the GO surface. Functionalization was confirmed by the study of X-ray diffraction (XRD) and Fourier transform infra-red spectroscopy (FTIR) characterization. Raman characterization was used for the study of defects on the functionalized GO surface. Langmuir–Blodgett technique was used for the deposition of a thin film. This deposited layer was used as a sensing layer for the detection of ammonia gas. Aluminum contacts were made for electrical measurement using thermal evaporation technique and annealed to obtain a good quality of contacts. The sensor behavior was observed for all three concentrations of PCBA and it has been observed that increase in PCBA concentration leads to the high sensor response and the maximum response was observed for the higher concentration of PCBA i.e. 75 mM. The senor was tested for different gas concentrations varied from 100 ppm to 1200 ppm. Also the selectivity and long term stability of prepared devices has been investigated.

Keywords

• Functionalization
• Graphene Oxide
• Gas sensor
• Langmuir-Blodgett