Uncertainty contributions in photocurrent linearity measurements of PV devices using a flash solar simulator

Especially for reference devices, the linearity of photocurrent over irradiance is an important characteristic that requires a low measurement uncertainty. This work investigates the uncertainty contributions when using a typical flash solar simulator with attenuation masks to determine the linearity characteristics of a device. Due to the complexity in measurement correlations, a Monte-Carlo simulation model was developed to estimate the final uncertainty. Results show that attenuation masks are not necessarily spectrally neutral and, if left uncorrected, this can significantly impact the measurement results. Furthermore, uncertainty in linearity is also dependent on the linearity of the sample under test itself. A shunted, non-linear device can have double the linearity uncertainty in low light conditions than a similar, linear sample.