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Cadmium telluride (CdTe) photovoltaics describes a photovoltaic (PV) technology that is based on the use of cadmium telluride, a thin semiconductor layer designed to absorb and convert sunlight into electricity.〔(【引用サイトリンク】title=Publications, Presentations, and News Database: Cadmium Telluride )〕 Cadmium telluride PV is the only thin film technology with lower costs than conventional solar cells made of crystalline silicon in multi-kilowatt systems.〔〔K. Zweibel, J. Mason, V. Fthenakis, "(A Solar Grand Plan )", ''Scientific American'', Jan 2008. CdTe PV is the cheapest example of PV technologies and prices are about 16¢/kWh with US Southwest sunlight.〕〔Further mention of cost competitiveness: "(Solar Power Lightens Up with Thin-Film Technology )", ''Scientific American'', April 2008.〕 On a lifecycle basis, CdTe PV has the smallest carbon footprint, lowest water use and shortest energy payback time of all solar technologies. CdTe's energy payback time of less than a year allows for faster carbon reductions without short-term energy deficits. The toxicity of cadmium is an environmental concern mitigated by the recycling of CdTe modules at the end of their life time,〔 〕 though there are still uncertainties〔 〕〔 (【引用サイトリンク】title=Water Solubility of Cadmium Telluride in a Glass-to-Glass Sealed PV Module ) 〕 and the public opinion is skeptical towards this technology.〔(【引用サイトリンク】title=The Lowdown on the Safety of First Solar’s CdTe Thin Film )〕〔(【引用サイトリンク】title=Cadmium: The Dark Side of Thin-Film? )〕 The usage of rare materials may also become a limiting factor to the industrial scalability of CdTe technology in the mid-term future. The rare abundance of tellurium—of which telluride is the anionic form—is comparable to that of platinum in the earth's crust and contributes significantly to the module's cost.〔(【引用サイトリンク】title=NREL: Manufacturing Analysis - Supply Constraints Analysis )〕 CdTe photovoltaics is used in some of the world's largest photovoltaic power stations, such as the Topaz Solar Farm. With a share of 5.1% of worldwide PV production, CdTe technology accounted for more than half of the thin film market in 2013.〔Fraunhofer ISE (Photovoltaics Report ), July 28, 2014, pages 18,19〕 A prominent manufacturer of CdTe thin film technology is the company First Solar, based in Tempe, Arizona. == Background == The dominant PV technology has always been based on crystalline silicon wafers. Thin films and concentrators were early attempts to lower costs. Thin films are based on using thinner semiconductor layers to absorb and convert sunlight. Concentrators lower the number of panels by using lenses or mirrors to put more sunlight on each panel. The first thin film technology to be extensively developed was amorphous silicon. However, this technology suffers from low efficiencies and slow deposition rates (leading to high capital costs). Instead, the PV market reached some 4 gigawatts in 2007 with crystalline silicon comprising almost 90% of sales.〔(Various estimates of world module production in 2007 )〕 The same source estimated that about 3 gigawatts were installed in 2007. During this period cadmium telluride and copper indium diselenide or CIS-alloys remained under development. The latter is beginning to be produced in volumes of 1–30 megawatts per year due to very high, small-area cell efficiencies approaching 20% in the laboratory.〔(【引用サイトリンク】title=NREL: News - Record Makes Thin-Film Solar Cell Competitive with Silicon Efficiency )〕 CdTe cell efficiency is approaching 20% in the laboratory with a record of 19.6% as of 2013. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Cadmium telluride photovoltaics」の詳細全文を読む スポンサード リンク
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