Solar cell spectral response measurement errors related to spectral band width and chopped light waveform

Abstract

An error in a spectral response measurement of a solar cell can occur when the response of the solar cell varies over the spectral range of the beam but is assumed to be the response at a single wavelength. It depends on the spectral shape and width of the beam that is incident on the solar cell. This analysis predicts the magnitude of the error for a variety of solar photovoltaic cells measured with monochromatic light sources of approximately 10-nm bandwidth. It also shows that, although these errors can be substantial at certain wavelengths, their consequences are relatively small for performance measurements that use the spectral response information to set solar simulator intensity. The error caused by use of too few monochromatic beams to characterize a cell's spectral response is illustrated. Bias errors related to the waveform of the chopped, monochromatic light are also discussed.