We separately investigated the amount of Ag + ions, surfactant composition, and total surfactant condition (Figure ). The UV/VIS/NIR spectra (Figures ) and TEM images (Figures ) were obtained with variable amounts of Ag + ions, two surfactant ratios, and surfactant mixture concentrations. For the Ag + ion, any conditions without first optimizing the concentrations demonstrated reduced efficiency of GNB synthesis (Figures and). The 0.25-foldratio condition only produced GNPs, while the 0.5-fold and 2-fold conditions yielded GNB with <55% efficiency (Figure ). The synthesized nanomaterials did not exhibit a uniform shape under these conditions. The surfactant compositions significantly changed the shape of the nanomaterial (Figures and). Without BDAC, a few GNBs were synthesized under our condition. When the BDAC:CTAB = 1:2 ratio was used, cross-shaped nanomaterials were observed at ~25% (Figure ). Notably, the synthesis of concave nanoparticles with rotational symmetry, such as nanostar synthesis, was still challenging . These data indicated the high potential of our system for synthesizing moderately symmetrical gold nanomaterial. Without CTAB, large and small percentages of GNPs and nanotriangles were observed (Figures and). A suitable amount of Ag + ion was essential for shape uniformity, and the ratio of BDAC determined the modest symmetrical shape of the nanomaterials, such as a cross or butterfly shape.