Size-controllable synthesis of NiCoSe2 microspheres as a counter electrode for dye-sensitized solar cells

• Published in: RSC advances 2018-07, Vol.8 (46), p.2647-2655
• Main Authors: Chen, Xiaobo, Ding, Jingguo, Li, Yan, Wu, Yinxia, Zhuang, Guoce, Zhang, Cuicui, Zhang, Zhihai, Zhu, Chengyun, Yang, Peizhi
• Format: Article
• Language: English
• Subjects: Charge transfer; Chemistry; Dye-sensitized solar cells; Dyes; Electrochemical impedance spectroscopy; Electrodes; Energy conversion efficiency; Microspheres; Morphology; Photovoltaic cells
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/c8ra04091e

NiCoSe 2 microspheres have been successfully synthesized by a facile one-step hydrothermal method at different hydrothermal temperatures. The prepared samples are divided according to their reaction temperatures (90, 120, 150 and 180 °C) and named NiCoSe 2 -90, NiCoSe 2 -120, NiCoSe 2 -150 and NiCoSe 2 -180, respectively. The diameters of the NiCoSe 2 microspheres strongly depend on the different hydrothermal temperatures. When the temperature is increased to 150 °C, the size of the resultant NiCoSe 2 microspheres changes from 200 to 800 nm, and the interior of NiCoSe 2 -150 possesses a flocculent structure. However, NiCoSe 2 -180 displays a cauliflower-like aggregated structure. The prepared NiCoSe 2 alloys are used as high-performance Pt-free counter electrodes (CEs) for dye-sensitized solar cells (DSSCs). Cyclic voltammogram measurement indicates that NiCoSe 2 -150 CE has larger current density than Pt CE. Electrochemical impedance spectroscopy shows that NiCoSe 2 -150 CE has a low charge-transfer resistance of 1.8 Ω cm 2 . Due to their unique morphologies and well-defined interior and exterior structures, DSSCs based on NiCoSe 2 -120 and NiCoSe 2 -150 CEs achieve high power conversion efficiencies of 8.48% and 8.76%, respectively, which are higher than that of the solar cell based on Pt CE (8.31%). The PCE value of the NiCoSe 2 -150-based DSSC is 8.76%, which is higher than that of DSSCs based on Pt (8.22%).