G. Balanagireddy¹, Ashwath Narayana^2, and M. Roopa^3,*

¹Department of Electronics & Communication Engineering, Rajiv Gandhi University of Knowledge Technologies, IIIT Ongole Campus, Ongole-516330, India

²Department of Bio-Medical Engineering, Rajiv Gandhi Institute of Technology, R.T. Nagar P.O., Hebbal, Bengaluru-560032, India

³Department of Electronics & Communication Engineering, Dayanand Sagar College of Engineering, Bengaluru-560078, India

*Corresponding author: E-mail: surajroopa@gmail.com

A low-cost and green-synthesized zinc oxide nanostructured particles are extensively studied owing to their remarkable and ample characteristics with less toxicity and eco-friendly approach. The present work comprehends the green synthesis of ZnO nanostructured particles using bougainvillea leaf extract-arbitrated microwave-assisted synthesis and their use in field effect transistor for nitrogen dioxide sensing at room temperature. The as-synthesized nanoparticles were characterized using analytical techniques; XRD determined the pure crystallite structure with no impurities, SEM confirmed the spherical shape of nanoparticles with ~20 nm (average particle size) and the atomic weight percentage were analyzed using EDAX, notable photophysical properties were revealed from absorption and emission spectra performed using UV-visible spectroscopy. Poly(3-hexylthiophene) and ZnO nanoparticles were employed in the field effect transistor (p-type) for NO₂ sensing at room temperature with the mobility (field-effect) of ~10^-4 cm² V^-1 s^-1. The sensitivity of the fabricated OFET device was extracted from the transistor characteristics (at Vgs = -30 V and Vds = -40 V) found to be ~4.8 × 10^-3 nA/ppm. The device exhibited engrossing characteristics such as excellent recoverability (> 95%), with ultrafast response time (< 30 s) and greater sensitivity with high stability as can be assessed from the electrical characteristics.

Bougainvillea, Poly(3-hexylthiophene), Zinc oxide nanoparticles, Nitrogen dioxide sensor.