Affiliations 

  • 1 Photonics Research Center, University of Malaya, Kuala Lumpur 50603, Malaysia. mahdiar@um.edu.my
  • 2 Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia. gholami897@gmail.com
  • 3 Photonics Research Center, University of Malaya, Kuala Lumpur 50603, Malaysia. laichoonkong@gmail.com
  • 4 Photonics Research Center, University of Malaya, Kuala Lumpur 50603, Malaysia. WuYi@um.edu.my
  • 5 Photonics Research Center, University of Malaya, Kuala Lumpur 50603, Malaysia. Harith@um.edu.my
  • 6 Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia. Yatima@um.edu.my
Sensors (Basel), 2015;16(1).
PMID: 26729115 DOI: 10.3390/s16010039

Abstract

An on-chip optical humidity sensor using Nano-anatase TiO₂ coating is presented here. The coating material was prepared so that the result is in solution form, making the fabrication process quick and simple. Then, the solution was effortlessly spin-coated on an SU8 straight channel waveguide. Investigating the sensitivity and performance (response time) of the device revealed a great linearity in the wide range (35% to 98%) of relative humidity (RH). In addition, a variation of more than 14 dB in transmitted optical power was observed, with a response time of only ~0.7 s. The effect of coating concentration and UV treatment was examined on the performance and repeatability of the sensor. Interesting observations were found, and the attributed mechanisms were described. In addition, the proposed sensor was extensively compared with other state-of-the-art proposed counterparts from the literature and remarkable advantages were found. Since a high sensitivity of ~0.21 dB/%RH and high dynamic performances were demonstrated, this sensor is proposed for use in biomedical applications.

* Title and MeSH Headings from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.