Facile Synthesis of Sub-20 nm Silver Nanowires Through a Bromide-Mediated Polyol Method

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1 Supporting Information for Facile Synthesis of Sub-20 nm Silver Nanowires Through a Bromide-Mediated Polyol Method Robson Rosa de Silva,, Miaoxin Yang, Sang-Il Choi, Miaofang Chi, Ming Luo, Chao Zhang, Zhi-Yuan Li, Pedro H. C. Camargo, # Sidney José Lima Ribeiro, and Younan Xia *,, The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332, United States Institute of Chemistry, São Paulo State University-UNESP, C P 355, , Araraquara, Brazil School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, United States Materials Science Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, United States Laboratory of Optical Physics, Institute of Physics, Chinese Academy of Science, Beijing , P. R. China # Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, , São Paulo, Brazil S1

2 Figure S1. Experimental (black) and calculated extinction spectra (red) using 3D-FDTD method for the transverse LSPR mode of Ag nanowires with a diameter of 20 nm. S2

3 Figure S2. Low-magnification TEM image taken from a sample of Ag nanowires prepared using the standard procedure (with a reaction time of 35 min). Nanowires longer than 20 µm can be easily identified, corresponding to an aspect ratio of >1000. S3

4 Figure S3. XRD pattern recorded from a sample of Ag nanowires prepared using the standard procedure (with a reaction time of 35 min). Because the enrichment of (111) planes in the Ag nanowires, the ratio of intensity between the (111) and (200) peaks is higher relative to the XRD pattern recorded the bulk silver (gray bar: JCPDS # ). S4

5 Figure S4. TEM images of products obtained using the standard procedure (with a reaction time of 35 min), except that the PVP with a molecular weight of g/mol was replaced by PVP with lower molecular weights at: (A) 10000, (B) 29000, (C) 40000, and (D) g/mol. S5

6 Figure S5. TEM images of Ag nanostructures prepared using the standard procedure (with a reaction time of 35 min) except for the replacement of NaBr by (A) NaCl and (B) NaI, respectively. The Ag nanowires displayed thicker diameters in the presence of Cl. On the other hand, irregular Ag nanoparticles were obtained when I was used and these nanoparticles tended to aggregate. S6

7 Figure S6. TEM images of Ag nanostructures obtained using the standard procedure (with a reaction time of 35 min), except for the reaction temperature was changed to (A) 140 C and (B) 150 C, respectively. S7

8 Table S1. The reported syntheses of Ag nanowires with diameters thinner than 50 nm. The thinnest diameter (nm) The greatest length (µm) Ref. 47 ± 3 28 [1] 40 ± 3 30 [2] 35 ± 6 12 [3] 34 ± 3 15 ± 7 [4] 30 ± 3 50 [5] [6] [7] 20 ± 2 40 ± 15 [8] [9] 6.4 ± [10] Reference (1) Luu, Q. N.; Doorn, J. M.; Berry, M. T.; Jiang, C.; Lin, C.; May, P. S. Preparation and Optical Properties of Silver Nanowires and Silver-Nanowire Thin Films. J. Colloid Interface Sci. 2011, 356, (2) Tang, X.; Tsuji, M.; Jiang, P.; Nishio, M.; Jang, S.-M.; Yoon, S.-H. Rapid and High-Yield Synthesis of Silver Nanowires Using Air-Assisted Polyol Method with Chloride Ions. Colloids Surfaces A Physicochem. Eng. Asp. 2009, 338, (3) Caswell, K. K.; Bender, C. M.; Murphy, C. J. Seedless, Surfactantless Wet Chemical Synthesis of Silver Nanowires. Nano Lett. 2003, 3, S8

9 (4) Zhu, J.; Xu, X.; Liu, J.; Zheng, Y.; Hou, S. Facile Synthesis of Oleylamine-Capped Silver Nanowires and Their Application in Transparent Conductive Electrodes. RSC Adv. 2015, 5, (5) Chang, M.-H.; Cho, H.-A.; Kim, Y.-S.; Lee, E.-J.; Kim, J.-Y. Thin and Long Silver Nanowires Self-Assembled in Ionic Liquids as a Soft Template: Electrical and Optical Properties. Nanoscale Res. Lett. 2014, 9, 330. (6) Sun, Y.; Yin, Y.; Mayers, B. T.; Herricks, T.; Xia, Y. Uniform Silver Nanowires Synthesis by Reducing AgNO 3 with Ethylene Glycol in the Presence of Seeds and Poly(Vinyl Pyrrolidone). Chem. Mater. 2002, 14, (7) Ran, Y.; He, W.; Wang, K.; Ji, S.; Ye, C. A One-Step Route to Ag Nanowires with a Diameter below 40 nm and an Aspect Ratio above Chem. Commun. 2014, 50, (8) Li, B.; Ye, S.; Stewart, I. E.; Alvarez, S.; Wiley, B. J. Synthesis and Purification of Silver Nanowires to Make Conducting Films with a Transmittance of 99%. Nano Lett. 2015, 15, (9) Lee, E.-J.; Chang, M.-H.; Kim, Y.-S.; Kim, J.-Y. High-Pressure Polyol Synthesis of Ultrathin Silver Nanowires: Electrical and Optical Properties. APL Mater. 2013, 1, (10) Eisele, D. M.; Berlepsch, H. V; Böttcher, C.; Stevenson, K. J.; Vanden Bout, D. a; Kirstein, S.; Rabe, J. P. Photoinitiated Growth of Sub-7 nm Silver Nanowires within a Chemically Active Organic Nanotubular Template. J. Am. Chem. Soc. 2010, 132, S9