Integrated Capacitive- and Resistive-Type Bimodal Relative Humidity Sensor Based on 5,10,15,20-Tetraphenylporphyrinatonickel(II) (TPPNi) and Zinc Oxide (ZnO) Nanocomposite

Rizwan Akram; Muhammad Saleem; Zahid Farooq; Muhammad Yaseen; Ziyad M Almohaimeed; Qayyum Zafar

doi:10.1021/acsomega.2c04313

Integrated Capacitive- and Resistive-Type Bimodal Relative Humidity Sensor Based on 5,10,15,20-Tetraphenylporphyrinatonickel(II) (TPPNi) and Zinc Oxide (ZnO) Nanocomposite

ACS Omega. 2022 Aug 21;7(34):30590-30600. doi: 10.1021/acsomega.2c04313. eCollection 2022 Aug 30.

Authors

Rizwan Akram¹, Muhammad Saleem², Zahid Farooq³, Muhammad Yaseen⁴, Ziyad M Almohaimeed¹, Qayyum Zafar²

Affiliations

¹ Department of Electrical Engineering, College of Engineering, Qassim University, P.O. Box 6677, Buraydah 51452, Saudi Arabia.
² Department of Physics, University of Management and Technology, Lahore 54000, Pakistan.
³ Department of Physics, Division of Science & Technology, University of Education, Lahore 54000, Pakistan.
⁴ Department of Chemistry, Division of Science & Technology, University of Education, Lahore 54000, Pakistan.

Abstract

The development of high-performance humidity sensors to cater for a plethora of applications, ranging from agriculture to intelligent medical monitoring systems, calls for the selection of a reliable and ultrasensitive sensing material. A simplistic device architecture, robust quantification of ambient relative humidity (% RH), and compatibility with the contemporary integrated circuit technology make a bimodal (capacitive and resistive) surface-type sensor to be a prominent choice for device fabrication. Herein, we have proposed and demonstrated a facile realization of a 5,10,15,20-tetraphenylporphyrinatonickel (II)-zinc oxide (TPPNi-ZnO) nanocomposite-based bimodal surface-type % RH sensor. The TPPNi macromolecule and ZnO nanoparticles have been synthesized by an eco-benign microwave-assisted technique and a thermal-budget chemical precipitation method, respectively. It is speculated from the morpohological study that specific surface area improvement, via the provision of ZnO nanoparticles on micro-pyramidal structures of TPPNi, may reinforce the sensing properties of the fabricated humidity sensor. The relative humidity sensing capacitive and resistive characteristics of the sensor have been monitored in 40-85% relative humidity (% RH) bandwidth. The fabricated sensor under the biasing conditions of 1 V of applied bias (V _rms) and 500 Hz AC test frequency exhibits a significantly higher sensitivity of 387.03 pF/% RH and 95.79 kΩ/% RH in bimodal operation. The average values of both the response and recovery times of the capacitive sensor have been estimated to be ∼30 s. It has also been debated why this high degree of sensitivity and considerable reduction in response/recovery time has been obtained. In addition, the intense and wide bandwidth spectral response of the TPPNi-ZnO nanocomposite indicates that it may also be utilized as a potential light-harvesting heterostructured nanohybrid in future studies.