Charge transporting enhancement of NiO photocathodes for p-type dye-sensitized solar cells

A p-type NiO film was prepared by doctor-blading of Ni(OH)2 paste onto FTO glass, followed by sintering at 450 °C for 30 min. The influence of nucleation condition of Ni(OH)2 on the morphology of NiO films and consequently charge transporting behavior is investigated. A smooth and compact NiO film is obtained with smaller Ni(OH)2 sol–gel particle size, which is confirmed by the surface topography examination. The hole transporting ability of NiO semiconductor is enhanced with such a compact film because of better interconnection between particles, as evidenced from electrochemical impedance analysis. The NiO film obtained is employed as the photocathode in p-type dye-sensitized solar cells (DSSCs) using arylamine-based dyes. The short-circuit photocurrent is two times improved to ca. 2.0 mA cm−2 compared to rough films.

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