Ultrafast Synthesis of Wavy Gold‐Silver Alloy Nanowires with Tunable Diameters in the Range of 2‐10 nm via a Seed‐Mediated Co‐Reduction

Abstract

We report an ultrafast synthesis of wavy gold-silver (AuAg) nanowires with tunable diameters via a seed-mediated coreduction. The success of current strategy relies on the use of an elevated reaction temperature to accelerate the synthesis to be completed within several minutes and the use of Au seeds with controlled sizes to enable the manipulation over their diameters in the range of 2-10 nm. The presence of chloride-contained quaternary ammonium surfactant and excessive reductant have been demonstrated to be critical for the highyield formation of AuAg products with the unique morphology of wavy nanowire. Due to the advantage in size control, the size effect on the plasmonic behavior of AuAg alloy wavy nanowires is investigated, where the products with sub-5 nm diameter exhibit a broad shoulder absorbance peak in their spectrum.

Tuning the Shape of Gold‐Silver Nanocrystals by Separately Controlling the Metal‐Atom Concentration in a One‐Pot Synthesis

“…For example, samples A1, B1, and C1 had two major morphologies: wavy wire and quasi-spherical particle. As indicated in our previous study, wavy wire had no prominent absorption peak in visible range [19] and the absorption peak located at ∼ 500 nm should be attributed to AuAg alloy quasispherical nanoparticles. The yield of quasi-spherical shape among the three samples increased in the order of A1 < B1 < C1, which contributed to the increase in the peak intensity.…”

“…As shown in Figure 1, the nine samples obtained using different combinations of precursor solution injection rates showed noticeable difference in terms of particle morphology and size. For example, for A1, a bunch of wavy nanowires were obtained at V Au =60 mL/h &V Ag =60 mL/h, indicating a fast co‐reduction of both Au and Ag precursors favors the formation of one‐dimensional products [19] . For A4 (V Au =60 mL/h &V Ag =4 mL/h), compared to A1, the decreased injection rate in Au precursor made the morphology of products dominated with plate‐like products.…”

“…For example, for A1, a bunch of wavy nanowires were obtained at V Au = 60 mL/h &V Ag = 60 mL/h, indicating a fast coreduction of both Au and Ag precursors favors the formation of one-dimensional products. [19] For A4 (V Au = 60 mL/h &V Ag = 4 mL/h), compared to A1, the decreased injection rate in Au precursor made the morphology of products dominated with plate-like products. In contrast, for A3 (V Au = 2 mL/h &V Ag = 60 mL/h), compared to A1, the decreased injection rate in Ag ChemistrySelect precursor led to the formation of polyhedral particles.…”

Detection of carcinoembryonic antigens using a wavy gold–silver alloy nanoplate enhanced surface plasmon resonance imaging biosensor

“…19 Compared to monometallic nanomaterials, their bimetallic counterparts have shown enhanced chemical, optical and electronic activities due to their physicochemical properties. 20,21 The introduction of silver to gold nanocrystals results in a hybrid material that not only retains the remarkable optical properties of both metals but also can be used as an effective route to tune the surface plasmon resonance properties.…”