A programmable solar simulator for realistic seasonal, diurnal, and air-mass testing of multi-junction concentrator photovoltaics

We built a spectrally programmable super-continuum solar simulator and applied it to the realistic laboratory testing of a multi-junction concentrator solar cell. The novel solar simulator generated a broad range of illumination conditions representing changes in time of day, time of year, and air mass. The simulator is based on a spatially coherent, super- continuum laser as the light source and a hybrid pair of prism- based spectrometers with spatial light modulators to precisely control the spectrum. The enhanced spectral coverage of this simulator significantly reduced the spectral mismatch over previous implementations. Geometries for both focused as well as divergent sample illumination were considered, achieving irradiances of approximately 100 suns and 190 suns, respectively. The measured performance of the cell was compared favorably to predictions based on both measured and theoretical spectra and representative quantum efficiency curves.