A photonic insight of NiO–GO nanocomposites synthesized by Adhatoda vasica extracts

Abstract

The low-cost, simple, and environmentally friendly green synthesis of nickel oxide nanoparticles (NiO) and related hybrids through plant extracts has gained a lot of interest nowadays. In this work, a one-step green synthesis of hybrid Nickel Oxide-Graphene oxide nanocomposites (NiO–GO NCs) utilizing an Adhatoda vasica extract was undertaken. Numerous analytical techniques, such as EDX, XPS, FESEM, HRTEM, XRD, Raman spectroscopy, FTIR, and UV–visible spectroscopy, were employed to assess the formation of NiO on GO. The study explored the light responsiveness of NiO–GO NCs by obtaining current–voltage (I–V) measurements under visible light exposure. The synthesized NiO–GO NCs exhibited remarkable and extensive sensitivity to light over a variety of wavelengths. Furthermore, responsivity and detectivity were maximum at 480 nm (9.83 mA/W, 2.53 × 10⁹ Jones), followed by 7.54 mA/W, 1.94 × 10⁹ Jones, and 3.98 mA/W, 1.02 × 10⁹ Jones, at 520 and 670 nm respectively. At 480 nm, with a biasing voltage as low as 1 nV, we got a responsivity of 6.91 µA/W and a detectivity of 5.15 × 10⁷ Jones. The photodetector showed a positive photoresponse between 5–30 V and a negative one between 1–100 nanovolts. This controllable approach for switching between positive and negative photoconductivity adds an extra functionality to conventional optoelectronic devices.