Eduardo CesarSolar cell blades convert solar energy into electricityEduardo Cesar
Researchers from the State University of Campinas (Unicamp) have obtained solar cells with the same degree of purity as the imported ones. “We started with 99% pure metallurgical silicon, supplied by the Rima company, from the State of Minas Gerais. We purified the silicon through a metallurgical process, by using an electron beam melting furnace, to obtain a purity of 99.999%,” says professor Paulo Roberto Mei, from the college of Mechanical Engineering. Professor Mei coordinates the research on solar cells, together with professor Francisco das Chagas Marques from the Physics Institute. The metallurgical route is simple and has no problems related to chemical waste as generated by the chemical process employed abroad to produce high-purity silicon. Brazil has the world’s highest quartz reserves and quartz is used to manufacture silicon. The country imports the blades used to produce photovoltaic panels. “Brazil exports metallurgical silicon at US$ 2 per kilo. After this is purified abroad, it is transformed into blades, used to make semiconductors or photovoltaic cells, that cost between US$ 50 and US$ 1,000, depending on the purity and the crystallinity,” says Mei. The Tecnometal company, based in the city of Campinas, is the only manufacturer of photovoltaic cells in Brazil and is a partner in this research project.
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