All-optical graphene oxide humidity sensors

Weng Hong Lim; Yuen Kiat Yap; Wu Yi Chong; Harith Ahmad

doi:10.3390/s141224329

All-optical graphene oxide humidity sensors

Sensors (Basel). 2014 Dec 17;14(12):24329-37. doi: 10.3390/s141224329.

Authors

Weng Hong Lim¹, Yuen Kiat Yap², Wu Yi Chong³, Harith Ahmad⁴

Affiliations

¹ Photonics Research Centre, University of Malaya, Kuala Lumpur 50603, Malaysia. wghglim@hotmail.com.
² Photonics Research Centre, University of Malaya, Kuala Lumpur 50603, Malaysia. yuenkiat@siswa.um.edu.my.
³ Photonics Research Centre, University of Malaya, Kuala Lumpur 50603, Malaysia. wuyi@um.edu.my.
⁴ Photonics Research Centre, University of Malaya, Kuala Lumpur 50603, Malaysia. harith@um.edu.my.

Abstract

The optical characteristics of graphene oxide (GO) were explored to design and fabricate a GO-based optical humidity sensor. GO film was coated onto a SU8 polymer channel waveguide using the drop-casting technique. The proposed sensor shows a high TE-mode absorption at 1550 nm. Due to the dependence of the dielectric properties of the GO film on water content, this high TE-mode absorption decreases when the ambient relative humidity increases. The proposed sensor shows a rapid response (<1 s) to periodically interrupted humid air flow. The transmission of the proposed sensor shows a linear response of 0.553 dB/% RH in the range of 60% to 100% RH.