Electrochemical Growth of FeS on Three-dimensional Carbon Scaffold as the High Catalytic and Stable Counter Electrode for Quantum Dot-sensitized Solar Cells

A low-cost, efficient and stable FeS/Carbon (FeS/C) composite counter electrode (CE), combining the excellent electrical conductivity of the carbon material and the superior catalytic activity of FeS, is prepared for quantum dot-sensitized solar cells (QDSCs) by electrochemical deposition of FeS on three-dimensional carbon mesoporous scaffold. The QDSC based on FeS/C CE achieves a rather high power conversion efficiency (PCE) of 4.58% with a fill factor (FF) of 0.51, which is much higher than those based on FeS/FTO CE (0.27) and C/FTO CE (0.11). Moreover, the FeS/C CE exerts excellent stability in photoelectric performance, which still performs high photoelectric conversion properties (PCE = 4.17%, V-oc = 0.42 V, J(sc) = 20.25mA.cm(-2) and FF = 0.49) after serving for 8 weeks. Besides, compared with conventional CEs based on conductive fluorine doped tin oxide (FTO) glass, FeS/C not only can work independently but also can be fabricated on various substrate forms (such as conductive or insulative, flexible or non-flexible), which is attributed to the facile preparation procedure and usage of conductive carbon paste. Therefore, the FeS/C has exhibited much promise as the CE in QDSCs. And our works have provided new insight into the material and structure optimization of CE for QDSCs. (C) 2015 Elsevier Ltd. All rights reserved.