Performance of n+-p silicon solar cells in concentrated sunlight

Performance data for n⁺-p silicon solar cells operating at illuminations up to 90 suns (9 W/cm²) and temperatures up to 100°C are presented. Experimental results for 2-cm²cells with different base resistivities are compared to performances predicted by a numerical device analysis computer code. Excellent agreement between numerical simulation and experiment is observed. For the illumination levels considered, an optimum base resistivity of approximately 0.3 Ω. cm is predicted by the numerical analyses and verified experimentally. The 0.3-Ω. cm cells exhibit conversion efficiencies above 11.8 percent up to 90 suns with a peak efficiency of 14 percent at approximately 30 suns. Preliminary results for a large-area (15.2 cm²) circular cell design are also presented for illuminations up to 60 suns. A peak conversion efficiency of 13.5 percent is measured for this cell at ∼25 suns.