Unidirectional self-assembly of Ag-Au nanoparticles using Aloysia Triphylla aqueous extract

This study presents the synthesis and characterization of self-assembled unidirectional nanostructures composed of silver-gold (Ag-Au) nanoparticles (NPs) produced through a green synthesis method using the Aloysia triphylla plant extract. The Ag-Au nanostructures were thoroughly characterized using scanning/transmission electron microscopy, X-ray diffraction, and UV–visible/Fourier-transform infrared spectroscopies. The resulting nanomaterial displayed compact arrays of Ag-Au NPs aligned along a single growth axis. Electron microscopy analysis revealed geometric arrangements measuring between 30 µm and 100 µm in length, with an average width of 0.5 µm. Notably, the unidirectional aggregates demonstrated unique characteristics resembling those of conventional crystalline materials. This unidirectional structure features a compact packing of nanoparticles, a phenomenon not previously observed using green synthesis methods. These findings highlight the unique assembly mechanisms and structural attributes of Ag-Au nanostructures synthesized through sustainable, mediated approaches.