Hydrothermal Synthesis of Silver Nanowires with Sub-20 nm Diameter and High Aspect Ratio

Silver nanowires (AgNWs) are attractive one-dimensional nanomaterials for transparent electrodes, sensors, and optoelectronic devices. In this study, ultrathin AgNWs were synthesized through a facile low-temperature hydrothermal strategy using silver nitrate (AgNO₃), cetyltrimethylammonium bromide (CTAB), and hexamethylenetetramine (HMTA) as raw materials. After systematic optimization, uniform AgNWs with an average diameter of 15 nm and a maximum aspect ratio of 2800 were successfully fabricated. AgBr colloids served as heterogeneous nucleation sites to form twinned seeds, and the coordinated reaction kinetics well balanced silver reduction and nanowire growth. The spray-coated AgNWs transparent conductive films on polyethylene terephthalate (PET) substrates exhibited outstanding optoelectronic performance with a sheet resistance of 45.1 Ω/sq, 92.1% transmittance, and a high FoM value. Moreover, reaction pressure and halide ion ratio were adjusted to regulate nanowire morphology. A pilot-scale synthesis was also completed, providing a reliable basis for the large-scale production and commercial application of AgNWs.