Scientists at Oxford University have developed a solvent system with reduced toxicity that can be used in the manufacture of perovskite solar cells, clearing one of the barriers to the commercialisation of a technology that promises to revolutionise the solar industry.Perovskites – a family of materials with the crystal structure of calcium titanate – have been described as a 'wonder material' and shown to be almost as efficient as silicon in harnessing solar energy, as well as being significantly cheaper to produce.