Silver Nanoparticles (Ag NPs) Skeleton Study by Transmission Electron Microscopy Technique: Structural Symmetry, Defects, Lattice Fringes and Phase Analysis Insights

Abstract

The crystallographic structure and defects of highly crystalline Ag NPs derived by chemical reduction were investigated using transmission electron microscopy (TEM). TEM revealed predominantly quasi-spherical to spherical nanoparticles (NPs) with a homogeneous morphology and an average particle size of 25.28 nm. Agglomeration analysis showed that 85.27 % of the particles were well dispersed, indicating effective growth control and good stability. The SAED patterns exhibited well-defined diffraction rings indexed to the (111), (200), (220), (311), and (222) planes, confirming the highly polycrystalline face-centred cubic (FCC) structure and phase purity. HR-TEM further revealed ordered lattice fringes with localised defects, and interplanar spacings of 0.235, 0.203, 0.144, 0.123, and 0.117 nm corresponded to the (111), (200), (220), (311), and (222) planes, respectively, confirming the highly crystalline FCC Ag structure and the presence of defects. The crystallographic analysis yielded lattice constants of a=b=c= 4.0772 Å (axial parameters), lattice angles of α=β=γ= 90°, and an Fm-3m space group, consistent with a standard FCC Ag crystal structure. EDS analysis confirmed 98.22 wt % Ag, demonstrating the high purity and structural integrity of the synthesised Ag NPs.