Compositional engineering of VOPcPhO-TiO2 nano-composite to reduce the absolute threshold value of humidity sensors

Mohamad Izzat Azmer; Fakhra Aziz; Zubair Ahmad; Ehsan Raza; Mansoor Ani Najeeb; Noshin Fatima; Tahani M Bawazeer; Mohammad S Alsoufi; R A Shakoor; Khaulah Sulaiman

doi:10.1016/j.talanta.2017.06.016

Compositional engineering of VOPcPhO-TiO₂ nano-composite to reduce the absolute threshold value of humidity sensors

Talanta. 2017 Nov 1:174:279-284. doi: 10.1016/j.talanta.2017.06.016. Epub 2017 Jun 7.

Authors

Affiliations

¹ Low Dimensional Materials Research Centre, Department of Physics, University of Malaya, 50603 Kuala Lumpur, Malaysia.
² Low Dimensional Materials Research Centre, Department of Physics, University of Malaya, 50603 Kuala Lumpur, Malaysia; Department of Electronics, Jinnah College for Women, University of Peshawar, Peshawar 25120, Pakistan.
³ Center for Advanced Materials (CAM), Qatar University, 2713 Doha, Qatar. Electronic address: zubairtarar@qu.edu.qa.
⁴ Department of Electronics, Faculty of Physical and Numerical Sciences, University of Peshawar, Peshawar 25120, Pakistan.
⁵ Center for Advanced Materials (CAM), Qatar University, 2713 Doha, Qatar.
⁶ Department of Electrical Engineering, Capital University of Science and Technology (CUST), Islamabad, Pakistan.
⁷ Department of Chemistry, Faculty of Applied Science, Umm Al-Qura University, Makkah, Saudi Arabia.
⁸ Mechanical Engineering Department, College of Engineering and Islamic Architecture, Umm Al-Qura University, Makkah, Saudi Arabia.

PMID: 28738579
DOI: 10.1016/j.talanta.2017.06.016

Abstract

This research work demonstrates compositional engineering of an organic-inorganic hybrid nano-composites for modifying absolute threshold of humidity sensors. Vanadyl-2,9,16,23-tetraphenoxy-29H,31H-phthalocyanine (VOPcPhO), an organic semiconductor, doped with Titanium-dioxide nanoparticles (TiO₂ NPs) has been employed to fabricate humidity sensors. The morphology of the VOPcPhO:TiO₂ nano-composite films has been analyzed by atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM). The sensors have been examined over a wide range of relative humidity i.e. 20-99% RH. The sensor with TiO₂ (90nm) shows reduced sensitivity-threshold and improved linearity. The VOPcPhO:TiO₂ (90nm) nano-composite film is comprised of uniformly distributed voids which makes the surface more favorable for adsorption of moisture content from environment. The VOPcPhO:TiO₂ nano-composite based sensor demonstrates remarkable improvement in the sensing parameter when equated with VOPcPhO sensors.

Keywords: Absolute threshold; Compositional engineering; Nano-composite; Relative humidity; VOPcPhO:TiO(2).