Review on Low‐Cost Counter Electrode Materials for Dye‐Sensitized Solar Cells: Effective Strategy to Improve Photovoltaic Performance

Abstract The photoelectric conversion efficiency (PCE) of dye‐sensitized solar cells (DSSCs) can be remarkably improved by optimizing the catalytic activity and charge transfer ability of the counter electrode (CE) materials. The attentive hotspots of CE catalysts for DSSCs are to design multifunctional materials that balance the fabrication cost, environmental friendliness, PCE, and electrochemical stability, then to achieve the substitution of the benchmark Pt. In this review, the four effective strategies are highlighted for further improving the photovoltaic performance of the DSSCs based on low‐cost CE materials, such as heteroatom‐doped materials, development of noble metal‐free chalcogenides with well‐controlled facets, construction of heterostructure, and synthesis of composites with a synergistic effect. In some typical examples, the influence of these strategies on catalytic activity, charge transfer ability, and reaction mechanism are elucidated by the theoretical calculation. Then the research opportunities and the challenges for the high‐efficiency DSSCs based on low‐cost CE materials are presented.