| Abstract |
| Cobalt silicide was used as a counter electrode to replace the Pt catalytic layer of a dye-sensitized solar cell (DSSC) device. 100 nm Si/ 100 nm Co on quartz were formed by sputtering, and cobalt-silicides were formed by vacuum heat treatment at 500 ℃ and 700 ℃ for 30 min, respectively. Field emission scanning electron microscopy (FE-SEM) was used to analyze the surface microstructure. X-ray diffraction (XRD) and Auger electron spectroscopy (AES) depth profiling analysis were used to confirm the phases. Also, cyclic-voltammetry (CV) analysis was employed to confirm the catalytic activity, and photovoltaic properties were confirmed using a simulator and potentiostat. The microstructure analysis indicated that the 500 ℃ and 700 ℃ silicidation led to a uniform planar layer, and island-like agglomerates, respectively. In the XRD and AES results, those phases were structures of quartz/CoSi/Co and quartz/dot-(CoSi2/Co). CV analysis showed that Si/Co and CoSi/Co exhibited catalytic activity, while dot-(CoSi2/Co) did not show catalytic activity due to the isolated dot structure. The energy conversion efficiencies of DSSCs with CoSi/Co and dot-(CoSi2/Co) were 3.75% and 0%, respectively, while that of Pt employed DSSC was 5.13%. Our result implies that using the nano-thick CoSi as a reduction catalytic layer may be an effective replacement for Pt. (Received March 4, 2016; Acceted July 22, 2016) |
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| Key Words |
| solar cells, annealing, phase transformation, auger electron spectroscopy, catalytic activity |
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