In-depth crystallographic structure and optoelectrical properties of ZnO nanoparticles synthesized by a facile precipitation method

Zinc oxide (ZnO) nanoparticles (NPs) were synthesized using a simple precipitation method. X-ray diffraction (XRD) analysis confirmed the formation of a hexagonal wurtzite phase (space group P63mc), with refined lattice parameters a = b = 3.308 Å and c = 5.196 Å, and a Zn–O bond length of 1.9654 Å. The atomic packing factor was calculated as 0.877, indicating a crystallinity of 97.01 %. Crystallite size, estimated through various models, ranged from 31.85 nm (Scherrer) to 61.08 nm (Williamson-Hall), with intermediate values from Monshi-Scherrer (45.47 nm), Halder-Wagner (34.67 nm), and Size-Strain Plot (53.62 nm) methods. Microstrain values varied between 0.0004724 and 0.0420, while residual stress and dislocation density were 65.30 MPa and 0.00046–0.00130 line/m², respectively. RMS strain values obtained from the SSP and Wilson methods were 0.001551 and 0.000389. A texture coefficient of 0.778 and a preferential growth of –0.25 indicated anisotropic crystal orientation. FESEM analysis showed particle sizes between 40.7 and 97.3 nm, and EDS confirmed the presence of Zn and O. UV–Vis spectroscopy revealed a direct bandgap of 3.25 eV, suggesting suitability for photovoltaic applications.