High Photovoltages of CuFeO2 Based P-Type Dye-Sensitized Solar Cells

Pure phase CuFeO2 powders with specific surface area of 6.5 m(2) g(-1) were synthesized by a self-combustion glycine nitrate process. The powders show a coral-like network structure with a wall thickness of about 100 nm and pore sizes ranging from tens of nanometers to hundreds of nanometers in diameter. The CuFeO2 powders were first applied as photocathodes for p-type dye-sensitized solar cells with coumarin 343 as sensitizer and iodide/triiodide (I-/I-3(-)) as redox mediator. The sintering process and thickness of the CuFeO2 photocathode films were roughly optimized. The optimized CuFeO2 based solar cell has achieved the best open circuit voltage of 365 mV under 1 Sun AM 1.5 illumination. This record is significantly high in comparison to p-DSSCs based on NiO or other delafossites tested in the similar LiI/I-2 electrolyte solutions. This is mainly due to the much deeper valence band (0.69 V vs. NHE) of CuFeO2 than that of the commonly used NiO (0.54 V vs. NHE). (C) 2016 Published by Elsevier B.V.