Mangifera indica–driven CuO nanoparticles: properties for sensing and optoelectronics

This study reports biological synthesis of Mangifera indica leaf extract–mediated copper oxide nanoparticles (CuO NPs). CuO NPs are characterized for crystal structure and crystallite size determination, absorption peak, particle size and morphological analysis, elemental composition, and functional groups’ identification using X-ray diffraction (XRD), ultraviolet–visible spectroscopy, high-resolution transmission electron microscope (HRTEM), field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectrometer (EDS), and Fourier transform infrared (FTIR). NPs show an absorption peak ∼338 nm and Tauc’s plot gives band gap energy ∼2.2 eV. XRD pattern depicts monoclinic phase ∼18 nm average crystallite size NPs. FESEM and HRTEM micrographs confirm the needle-shaped NPs having 5:40 nm aspect ratio. The EDS spectrum, depicting the Cu and O peaks, shows that the particles are free from any type of impurity. FTIR analysis elucidates the role of bioactive chemicals in the extract in the successful formation of NPs. The photoluminescence study reveals the existence of violet, green, orange, yellow, and red emission bands. Also, NPs exhibit an electrical conductivity of 1.37 × 10^–7 S/m and 5. 31 × 10^–7 S/m at 100°C and 200°C. Thus, environmentally friendly, non-toxic, green-synthesized CuO NPs hold significant potential for applications in resistive sensors, solar cells, and optoelectronics devices.