Thus, in the case of current conduction, the temperature of the nanowires rises due to Joule heating, and the instability of the nanowires at these temperatures causes the electrodes to fail. The measured surface temperature Selleck Bucladesine of the 12 Ω/sq electrode under 17 mA/cm2 of current flow was 55°C

at the time of failure. Comparing the time to failure of this electrode to the time for the nanowires in the annealed samples to break up, we estimate that the temperature of the nanowires themselves in this particular case was between 100°C and 150°C. Elechiguerra et al. found that silver nanowires synthesized by the polyol method corrode in the atmosphere [6]. Rather than corroding by reacting with oxygen, silver GM6001 order corrodes due to reduced sulfur gases present in the air. They observed that after 3 weeks, silver sulfide (Ag2S) nanoparticles started to form on the surface of the nanowires, and after 6 months, some of the nanowires became discontinuous. In our experiments, nanoparticles and breakage occur much faster. EPZ015938 mouse corrosion is greatly enhanced at elevated temperatures [18]. EDS spectra were taken from the nanoparticles decorating the surface of the nanowires after electrode failure (Figure 5). Other than the carbon and copper signals originating from the TEM grid, only silver

and sulfur were detected. The ratio of silver to sulfur content was 9:1. The presence of sulfur indicates that the electrodes may have failed due to the corrosion of the nanowires in the atmosphere at the elevated temperatures

caused by Joule heating. Figure 5 Energy-dispersive spectrum of a nanoparticle formed on a silver nanowire after electrode failure. The ‘x’ indicates the location where the measurement was taken. Sulfur was detected in the nanoparticles Sclareol indicating corrosion of the silver. Alternatively, or addition to corrosion, another reason for the breakup of the silver nanowires at increased temperatures could be attributed to the high surface energy of the nanowires. Nanowires have a large surface-area-to-volume ratio, and the sidewalls of the nanowires used in the electrodes are all 110 planes [19], which are not the lowest energy planes in an FCC material. At elevated temperatures, atomic diffusion is increased, and kinetic limitations to reconstruction can be overcome. Silver nanobelts and nanowires of other metals have been shown to fragment at temperatures far below their bulk melting temperatures due to Rayleigh instability [20, 21], and a similar phenomenon may be occurring here. Our data indicate that the Joule heating effect elevates the temperature of silver nanowire electrodes, which leads to nanowire instability and ultimately electrode failure. More studies are required to determine whether the instability of silver nanowires at elevated temperatures in air is due to corrosion, Rayleigh instability, or another mechanism.