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The modern age of solar cells
Today, there are thousands of issued patents, both US and worldwide, on various solar cell technologies. Accompanying this explosion in green technological innovation, cumulative solar photovoltaic installed capacity worldwide has soared due to improved conversion efficiency and lowered volume production costs. For example, worldwide solar photovoltaic capacity had grown to 512 Gigawatts by the end of 2018 (representing 27% growth from 2017),18 accompanied by a steady decrease in system and installation costs. Besides single-crystal technologies, research has also focused on polycrystalline silicon, organic, and thin-film technologies.
While cheaper, these technologies do not provide the high conversion efficiency of single-crystal technologies. For example, in addition to silicon, which is in Group IV of the periodic table, researchers have developed solar cells from Group III and Group V (or even Group VI) materials. By 1972, IBM had developed an aluminum-gallium-arsenide based solar cell with between 18% and 20% conversion efficiency.19 Others have since demonstrated over 35% conversion efficiency for such cells.20
Continued innovation, incentivized by strong intellectual property protection regimes, will only bring further improvements in efficiency and costs, making green solar technology more accessible to consumers everywhere.
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