In this study, we demonstrate a facile, one-pot, and low-temperature (∼85 °C) chemical bath method for the preparation of a composite of cobalt selenide/graphene (Co_0.85Se/Gr) as the electrocatalyst for the counter electrode (CE) of dye-sensitized solar cells (DSSCs) with a cobalt-based electrolyte. The Co_0.85Se/Gr composite film was envisaged to have the advantages of both components, that is, the high electrochemical surface area of Co_0.85Se and the straight paths for electron transfer from Gr. The DSSCs with Co_0.85Se/Gr exhibited a power conversion efficiency (η) of 11.26%. According to the results of the rotating disk electrode, the film of Co_0.85Se/Gr showed a high electrocatalytic surface area (A_e) and an extremely large intrinsic heterogeneous rate constant (k₀). Furthermore, the composite film of Co_0.85Se/Gr exhibits a high transparency in the wavelength region of 400–800 nm (>82%), which implied that the corresponding electrode shall be a potential CE in rear-side illuminated DSSCs. The photovoltaic parameters of the DSSCs with Pt, Co_0.85Se, Gr, and Co_0.85Se/Gr were obtained for rear-side illumination and additionally for front- and rear-side illuminations (AM 1.5, 100 mW/cm²) using different electrolytes. As the cobalt-based electrolyte of [Co(bpy)₃]^2+/3+ exhibited a low light absorption and low overpotential for dye regeneration, a rear-side illuminated DSSC with a cobalt-based electrolyte showed the highest efficiency of 9.43 ± 0.02%, which is greater than that of the DSSC with an I^–/I₃^–-based electrolyte (η = 7.63 ± 0.04%).

中文翻译：

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透明的硒化钴/石墨烯对电极，用于基于Co2 + / 3 +的氧化还原对的高效染料敏化太阳能电池。

在这项研究中，我们证明了一种简便，一锅且低温（〜85°C）的化学浴方法，用于制备硒化钴/石墨烯（Co _0.85 Se / Gr）复合材料作为计数器的电催化剂。钴基电解质的染料敏化太阳能电池（DSSC）的电极（CE）。设想Co _0.85 Se / Gr复合膜具有两种成分的优点，即Co _0.85 Se的高电化学表面积和从Gr转移电子的直线路径。Co _0.85 Se / Gr的DSSC的功率转换效率（η）为11.26％。根据旋转圆盘电极的结果，Co _0.85 Se / Gr膜显示出高的电催化表面积（a _e）和极大的固有异质速率常数（k ₀）。此外，Co _0.85 Se / Gr复合膜在400–800 nm的波长区域（> 82％）具有很高的透明度，这意味着在背面照亮的DSSC中，相应的电极应为电势CE。获得了Pt，Co _0.85 Se，Gr和Co _0.85 Se / Gr的DSSC的光伏参数，用于后侧照明，另外还使用不同的前侧和后侧照明（AM 1.5，100 mW / cm ²）电解质。作为[Co（bpy）₃ ] ^{2 + / 3 +}的钴基电解质表现出低的光吸收率和低的染料再生过电位，带有钴基电解质的后照式DSSC的最高效率为9.43±0.02％，高于I ^– / I ₃ ^–的DSSC ^。电解质（η= 7.63±0.04％）。