Mitsubishi Electric Corp. has announced its achievement of a photoelectric conversion efficiency rate of 18.0% in a 150 mm square practical use polycrystalline silicon solar cell.
The assessment was conducted by the National Institute of Advanced Industrial Science and Technology (AIST), a public verification agency.
This achievement allows 7% more power generation per area and enables limited space installation, such as a small roof, to secure a sufficient amount of power generation.
This solar cell has incorporated three proprietary technologies in an effort to increase efficiency. First, the reflectivity from the acceptance surface has been reduced through RIE (reactive ion etching) microfabrication using a nano-sized mask material, increasing the amount of absorbed light.
Second, the lowering of electrical performance in crystalline has been suppressed through a new electrode material. Third, the effective electrical output surface area has been expanded by thinning grid collector electrodes. Through these technologies, Mitsubishi achieved the world's highest conversion efficiency of 18%.
The company plans to sequentially introduce these technologies to its solar cells and release solar cell module products. Mitsubishi also plans to present this achievement at the "17th International Photovoltaic Science and Engineering Conference," which will be held in Fukuoka in December 2007.
The above-mentioned technology to reduce reflectivity from the acceptance surface is partly based on the result of the Project for R&D of Innovative Next Generation Photovoltaic System Technology" commissioned by the NEDO (New Energy and Industrial Technology Development Organization).