Structural, optical and electrical properties of undoped and doped (Al, Al + Mn) ZnO nanoparticles synthesised by green combustion method using terminalia catappa seed extract. (2022)

• Record Type: Journal Article
• Authors: Savitha, D.; Latha, H.K.E.; Lalithamba, H.S.; Mala, S.; Vasudev Jeppu, Yogananda
• Is Part Of: Materials today. Volume 60:Part 2(2022)
• Page Start: 988
• Page End: 997
• Publication Date: 2022
• Subjects: Materials science -- Congresses -- Periodicals; 620.1
• DOI: 10.1016/j.matpr.2021.12.365
• Languages: English
• ISSNs: 2214-7853

Abstract

Highlights: This paper focus on green synthesis of undoped and doped ZnO nanoparticles by combustion method. ZnO nanoparticles are synthesized using zinc nitrate precursor, Aluminium nitrate and magnesium as dopant and Terminalia catappa seed extract as fuel. Effect of doping (Al, Al + Mn) on microstructural, optical and electrical properties of ZnO nanoparticles are investigated. The green synthesized doped and undoped ZnO nanoparticles exhibits hexagonal wruzite structure with highly crystallinity. Synthesized ZnO nanoparticles shows porous structure, with increase in mean grain size for Al doped ZnO nanoparticles. FTIR analysis confirms the formation of Zn-O bonding at 462, 439 and 455 cm −1 for undoped, Al doped and Al + Mn doped ZnO nanoparticles. Abstract: This paper presents the synthesis of undoped and doped (Al, Al + Mn) ZnO nanoparticles by green combustion method using Terminalia Catappa seed extract as a novel fuel and Zinc nitrate as a precursor, Aluminum nitrate and Magnesium chloride was used as dopant. Synthesized undoped and doped ZnO nanoparticles were characterized by XRD, FESEM, FTIR, UV-visible spectroscopy and impedance spectroscopy. The XRD study of undoped and doped (Al, Al + Mn) ZnO nanoparticles exhibits hexagonal wurtzite structure with high crystallinity. The crystallite size increases from 37.5 nm to 39 nm for Al doping and decreased to 30.5 nm for Al + Mn doped ZnO nanoparticles. Mean grain size of undoped ZnO nanoparticles was found to be 32.5 nm. For Al doped ZnO nanoparticles mean grain size increases (42.9 nm) and then decreases (21.25 nm) for Al + Mn doped ZnO nanoparticles. FTIR studies confirms the formation of Zn-O bond at 462, 455 and 439 cm −1 for both undoped and doped ZnO nanoparticles. The optical band gap was found to be 3.25, 3.2 and 2.54 eV for undoped and doped (Al, Al + Mn) ZnO nanoparticles respectively. The dielectric properties and conductivity studies were carried for undoped and doped (Al, Al + Mn) ZnO nanoparticles at various fixed temperatures (50 to 350 °C) by varying frequency from 10 Hz to 8 MHz. Dielectric constant increases with rise in temperature and, dielectric constant decreases with rise in frequency and remains constant at higher frequency. At lower frequencies AC conductivity was constant and increases as the frequency increases. Grain and grain boundary resistance for the synthesised ZnO nanoparticles were studied by complex impedance analysis and result exhibits a decrease in grain resistance with rise in temperature. The ZnO nanoparticles doped with Al shows improved microstructural properties, decreased optical band gap and activation energy. Hence these nanoparticles are suitable material for sensors and optoelectronics applications.