Theoretical design and performance of InxGa1-xN two-junction solar cells

The efficiencies of InxGa1-xN two-junction solar cells are calculated with various bandgap combinations of subcells under AM1.5 global, AM1.5 direct and AM0 spectra. The influence of top-cell thickness on efficiency has been studied and the performance of InxGa1-xN cells for the maximum light concentration of various spectra has been evaluated. Under one-sun irradiance, the optimum efficiency is 35.1% for the AM1.5 global spectrum, with a bandgap combination of top/bottom cells as 1.74 eV/1.15 eV. And the limiting efficiency is 40.9% for the highest light concentration of the AM1.5 global spectrum, with the top/bottom cell bandgap as 1.72 eV/1.12 eV.

National Natural Sciences Foundation of China 60576046 60606002Knowledge Innovation Engineering of Chinese Academy of Sciences YYYJ-0701-02 State Key Development Program for Basic research of China 2006CB604905 513270505This work is supported by the National Natural Sciences Foundation of China (No. 60576046, No. 60606002), the Knowledge Innovation Engineering of Chinese Academy of Sciences (No YYYJ-0701-02) and the State Key Development Program for Basic research of China (No. 2006CB604905, No. 513270505).