Electrocatalytic carbonaceous materials for counter electrodes in dye-sensitized solar cells

Carbonaceous materials have received much attention as alternative catalysts for platinum in dye-sensitized solar cells. Recently, various forms of carbon materials have been intensely investigated due to their low cost, excellent electrochemical stability, reasonable catalytic activity, and process adaptability. In this review, we introduce the current research issues in carbon counter electrodes including the equivalent circuit analysis, the electrochemical properties, the photovoltaic performances, and the research outlook. In this regard, the electrochemical properties of selected carbon materials are compared with each other by means of the impedance spectroscopy and equivalent circuit analysis. Also, fabrication methods and related photovoltaic performance are discussed. This knowledge will offer valuable insight to inspire investigation of carbon materials and encourage a multitude of applications ranging from all-carbon electrodes to flexible devices.