Nanoporous NiO has been commonly used in p-type dye-sensitized solar cells (p-DSCs) as a p-type �semiconductor� for accepting and transporting holes injected from photo-excited sensitizers. However,  NiO is in fact a Mott insulator. Ni(II) has the partially filled and localized 3d-orbitals. The band structure resulting from the orbital overlap is not accurate for describing the electronic properties of NiO. What controls the photovoltage in NiO-based p-DSCs? How to describe the hole-transport in NiO? Is the transport a bulk property or just a surface property of NiO? These basic questions have not been well elucidated. In this presentation, I will discuss our recents efforts in interpreting NiO-based p-DSCs based on the interfacial redox process of NiO. From this perspective, a NiO p-DSC is essentially a photo-driven supercapactior. The implication to the interpretation of photovoltage, the fast recombination and the low fill factor will be discussion. This model should be applied to other transition metal oxides with surface redox activities.

Understanding nanoporous NiO in p-type dye-sensitized solar cells

246th National Meeting (2013)

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