Mitsubishi touts 18.6% efficient solar cell

Mitsubishi Electric says it has built a multicrystalline silicon solar cell with a "record" conversion efficiency of 18.6%

Mitsubishi touts 18.6% efficient solar cell

Mitsubishi Electric says it has built a multicrystalline silicon solar cell with a "record" conversion efficiency of 18.6%, achieving the mark by adding a low-reflectivity surface texture, optimizing the p-n junction to increase electric current generation, and incorporating a new metallization process that reduces shade loss of front grid electrodes.

For highly efficient PV cells, a honeycomb-textured structure is typically seen as suitable to reduce surface reflectivity, but a challenge to incorporate into production. The company says it has developed a method to fabricate such a structure on the surface of a 150mm multicrystalline silicon substrate, combining laser patterning and wet etching.

Further, the company says it is using a shallower, lightly doped emitter (n-layer) to increase light gain and improve power generation efficiency. And it says using modified screens and front metal electrodes reduces shading loss of front grid electrodes by 25% vs. previous cells.

Mitsubishi Electric says it has 18 domestic and seven international patents pending for this work, which it will present at the 23rd European Photovoltaic Conference in September in Spain. Introduction into mass production of the company's photovoltaic modules is planned for fiscal 2011 (starting April 2010). The company also aims to combine the technology with its high-efficiency PV inverters to increase output of solar power generation systems.