Assembly, charge-transfer and solar cell performance with porphyrin-C60 on NiO for p-type dye-sensitized solar cells

A series of zinc tetraphenylporphyrin photosensitizers furnished with three different anchoring groups, benzoic acid, phenylphosphonate and coumarin-3-carboxylic acid, were prepared using click methodology. All three gave modest performances in liquid junction devices with I3/I as the electrolyte. The distinct spectroscopic properties of the porphyrins allowed a detailed investigation of the adsorption behaviour and kinetics for charge transfer at the NiOporphyrin interface. The adsorption behaviour was modelled using the Langmuir isotherm model and the phosphonate anchoring group was found to have the highest affinity for NiO (6.65104M1) and the fastest rate of adsorption (2.46107cm2mol1min1). The photocurrent of the p-type dye-sensitized solar cells increased with increasing dye loading and corresponding light harvesting efficiency of the electrodes. Coordinating the zinc to a pyridyl-functionalized fullerene (C60PPy) extended the charge-separated state lifetime from ca 200ps to 4ns and a positive impro...