{"id":7993,"date":"2013-07-06T08:39:26","date_gmt":"2013-07-06T15:39:26","guid":{"rendered":"http:\/\/cafe.foundation\/blog\/?p=7993"},"modified":"2013-07-06T08:39:26","modified_gmt":"2013-07-06T15:39:26","slug":"anti-freeze-could-lower-cost-of-solar-cells","status":"publish","type":"post","link":"http:\/\/cafe.foundation\/blog\/anti-freeze-could-lower-cost-of-solar-cells\/","title":{"rendered":"Anti-freeze Could Lower Cost of Solar Cells"},"content":{"rendered":"

We\u2019ve examined many attempts to make solar cells, batteries and fuel cells less expensive and to use abundant, easily found materials in their manufacture.\u00a0 Engineers at Oregon State University in Corvallis, Oregon may have crafted a process to manufacture budget solar cells with anti-freeze<\/a>\u00a0and relatively cheap metals as key components.<\/p>\n

Ethylene glycol, found in many automotive antifreeze products, acts as a low-cost solvent \u201cthat functions well in a \u2018continuous flow\u2019 reactor,\u201d according to OSU, \u201can approach to making solar cells that cost less and avoid toxic compounds, while further expanding the use of solar energy.\u201d<\/p>\n

The last sentence stopped your editor cold, since ethylene glycol is a neurotoxin, playing havoc with brains, livers and kidneys.\u00a0 Reading the researchers\u2019 paper published in Material Letters<\/em><\/a> and available online, perhaps the effects of flowing the cells\u2019 metallic materials through a meso-fluidic reactor with the antifreeze neutralizes the toxins, but that isn\u2019t spelled out clearly (at least for your non-chemist editor).<\/p>\n

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Nano metals floated in antifreeze to make inexpensive solar cells<\/p><\/div>\n

\u201cMetallic materials\u201d refers to \u201cCZTS, or copper zinc tin sulfide, a compound of significant interest for solar cells due to its excellent optical properties and the fact these materials are cheap and environmentally benign.\u201d<\/p>\n

Promoting the budget approach, Greg Herman, an associate professor in the OSU School of Chemical, Biological and Environmental Engineering, says, \u201cThe global use of solar energy may be held back if the materials we use to produce solar cells are too expensive or require the use of toxic chemicals in production.\u00a0 We need technologies that use abundant, inexpensive materials, preferably ones that can be mined in the U.S. This process offers that.\u201d<\/p>\n

OSU notes that many current solar cells are made with CIGS, or copper indium gallium diselenide, more rare and costly overall than the CZTS solution.\u00a0 Indium, for instance is mostly produced in China and combined with gallium is priced about 275 times higher than the zinc in OSU\u2019s cells.<\/p>\n

Continuous flow processing speeds up processing the materials, too, taking only a half hour to make the same amount of material that would take a full day for CIGS materials made in \u201cbatch mode.\u201d\u00a0 This speed, combined with \u201cprecise control of temperature, reaction time, and mass transport [will] yield better crystalline quality and high uniformity of the nanoparticles that comprise the solar cell.\u201d<\/p>\n

Controlling temperature and time in the metallic soup apparently helps to size metallic nano-particles to their optimums for best solar collection efficiency.<\/p>\n

As a final grace note, Herman adds, \u201cFor large-scale industrial production, all of these factors \u2013 cost of materials, speed, quality control \u2013 can translate into money.\u00a0\u00a0 The approach we\u2019re using should provide high-quality solar cells at a lower cost.\u201d<\/p>\n

When the fluidic process is perfected, the materials might be cooked in a large microwave oven \u201csimilar to the one in most kitchens.\u201d<\/p>\n

Thin film cells have lower performance than the best silicon solar cells, and initial CZTS figures are lower than those for CIGS so far, but further research on dopants and other factors should result in comparable efficiencies.<\/p>\n

This project is one result of work through the Center for Sustainable Materials Chemistry, a collaborative effort of OSU and five other academic institutions, supported by the National Science Foundation. Funding was provided by Sharp Laboratories of America. The goal is to develop materials and products that are safe, affordable and avoid the use of toxic chemicals or expensive compounds.<\/p>\n