Study on the synthesis of silver nanowires with adjustable diameters through the polyol process

Abstract

Silver nanowires with adjustable diameters ranging from 20 to 500 nm have been synthesized by introducing certain control agents into the conventional polyol process. These control agents can be classified into three types: inorganic anions, metal cations, and molecules. The as-synthesized nanowires also exhibit size dependent UV-vis absorption spectra, which are meaningful to the fabrication of nanodevices. It is presumed that the control agents could influence the size of the initial nucleus and therefore the diameters of the final nanowires through forming silver salt colloids or varying the rate of silver reduction. This synthetical strategy may also provide a versatile route to prepare nanomaterials with well-defined diameters.

Comprehensive Synthesis Study of Well-Dispersed and Solution-Processed Metal Nanowires for Transparent Heaters

“…For all subsequent syntheses, the process time was kept at 30 min to ensure a completed wire growth. This time compares well or is even shorter than studies that report a duration of 30 min [28], 60 min [6,29,30], and 120 min [31] for their standard process.…”

“…Finally, for the synthesis section of this work, the effect of the addition of the halide KCl was studied. So far, a few studies have presented the use of halides such as KBr for the synthesis of AgNWs and reported a reduction in diameter [28,31,42,46,47]. For adding different concentrations of KCl (3-15 wt.%, see supporting information Figure S-6), we have also observed a modulation in diameter, which lies in the range of 78-114 nm.…”

“…∘ C [6,29], and 170 ∘ C [30] to 180 ∘ C [31]. For this study, a careful temperature calibration was performed using a Pt100 thermoresistor that is placed in the heated EG solution to give the exact temperature.…”

“…The occurrence of an optimum growth temperature was reported earlier [28,33] and can be explained as follows: the higher the process temperature the higher the reduction of Ag + -ions to neutral Ag 0 -atoms that can contribute to the wire formation faster and lead to longer wires. However, the binding of the capping agent to the (111) plane that should be reserved exclusively for Ag 0 -atoms is also enhanced for increased temperatures [31]. The supply of Ag 0 -atoms that is enhanced for higher temperatures goes alongside with a decreased selectivity of the capping agent PVP, which in turn leads to an optimum for the temperature.…”

“…The chain lengths of the PVP are composed of vinylpyrrolidone monomers with an elemental formula of C 6 H 9 NO. Most studies report the use of PVP with a MW of 40 k [6,30,31], 55 k [29,32,35], 360 k [38,40] as well as 1,3 M [41][42][43]. Song et al [43] and Zhu et al [44] investigated the effect of the MW of PVP on the yield and shape of AgNWs.…”