Nanoco Group, a firm which makes tiny semi-conductors, has agreed to continue its relationship with the Japanese company Tokyo Electron to develop cheap solar cells.The technology involves creating so-called "cadmium free quantum dots". In normal English this means manufacturing incredibly small droplets that in the right conditions can produce electricity.Nanoco makes "solar ink" so these droplets can be printed on to a film and then used in solar panels. The potential business advantage of this technology is that it would be much cheaper than the current types of solar cells which require significant upfront costs to manufacture.Nanoco says it will receive "milestone payments" for its work in improving the performance of the solar film they two companies have already produced.Michael Edelman, Nanoco's Chief Executive, said: "We are delighted to enter the second phase of this (agreement) after exceeding all of the milestones in the initial phase. We have been particularly pleased with progress to date, which underlines the potential of our technology in the solar power sector to replace highly capital intensive processes with high-tech chemistry." Nanoco's share price rose 4% on the announcement.BS