Humidity sensor properties of hydrothermally grown rutile-TiO2 microspheres on interdigital electrodes (IDEs)

• Published in: Journal of materials science. Materials in electronics 2022-05, Vol.33 (15), p.11825-11840
• Main Authors: Hase, Yogesh, Sharma, Vidhika, Doiphode, Vidya, Waghmare, Ashish, Punde, Ashvini, Shinde, Pratibha, Shah, Shruti, Rahane, Swati, Vairale, Priti, Bade, Bharat, Jadhav, Yogesh, Prasad, Mohit, Rondiya, Sachin, Rokade, Avinash, Jadkar, Sandesh
• Format: Article
• Language: English
• Subjects: Annealing; Argon; Characterization and Evaluation of Materials; Chemistry and Materials Science; Electrodes; Humidity; Materials Science; Microspheres; Morphology; Optical and Electronic Materials; Raman spectroscopy; Recovery time; Relative humidity; Rutile; Sensors; Spectrum analysis; Synthesis; Thin films; Titanium dioxide
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-022-08146-4

Rutile-TiO 2 microspheres were synthesized by the single-step hydrothermal method and were subsequently annealed in an argon environment at 200 °C, 400 °C, and 600 °C. The influence of annealing temperature on structural, optical, morphological, and humidity sensing performance of rutile-TiO 2 microspheres was examined. As-synthesized and annealed rutile-TiO 2 microspheres were characterized using different characterization techniques. SEM confirmed the spherical shape morphology of TiO2 microspheres. XRD confirmed the tetragonal structure and rutile phase of TiO 2 microspheres. The rutile phase of TiO 2 was also confirmed by Raman spectroscopy. No significant change in the bandgap has been observed in rutile-TiO 2 with increased annealing temperature. The presence of various chemical groups in rutile-TiO 2 microspheres was studied using FTIR spectroscopy. The Brunauer–Emmett–Teller (BET) and Barrett–Joyner–Halenda (BJH) analysis showed a decrease in surface area and pore volume and an increase in average pore radius with an increase in annealing temperature. The humidity sensing performance of TiO 2 microspheres thin films deposited on interdigital electrodes (IDEs) was studied between 11 to 97% relative humidity (RH). The humidity sensor fabricated using rutile-TiO 2 microspheres annealed at 600 °C showed excellent humidity sensing properties. The sensor has the highest sensitivity (~ 71.5%), fast response, and recovery time of ~ 11.1 s and ~ 0.8 s, respectively.