All-solid state dye-sensitised solar cells (DSCs) have experienced an impressive growth this year. In these cells the liquid electrolyte is replaced by a solid semiconductor, which can be processed from solution and then penetrate easily the nanoporous matrix of the TiO2. These novel semiconductors belong to the perovskites family and they can even act as the light absorber and the hole or electron conductor.
Apart from the Nature paper from Mercouri Kanatzidis' Group, where they show a cell with CsSnI2.95F0.05 exceeding 10% efficiency, Henry Snaith and his collaborators have reported a 10.9 %
efficiency DSC based on the CH3NH3PbI2Cl perovskite. Surprisingly this result has been achieved without using TiO2. A nanostructured insulating Al2O3 film serving as a "scaffold" suffices to obtain this outstanding achievement. The perovskite itself conducts electrons more quickly than the TiO2. These results has been recently published in Science and Dr. Henry Snaith has set up a spin-out company from Oxford University to develop and commercialise this novel technology and all the intellectual property created by his group during their intense research. Oxford Photovoltaics is the name of this company that focus its efforts in building integrated photovoltaics.
However, despite the success of these novel devices, the scientific community have expressed concerns about the
reproducibility and stability of some of the reported devices. We will probably have to wait some time to see that other groups are able to
reproduce these results and they can be produced on a large scale. This final task is now under development at Oxford Photovoltaics.
