Ultrashort Laser Pulses for Electrical Characterization of Solar Cells

Abstract

The ability to provide highly accurate performance evaluations of photovoltaic devices has never been more important given the recent, and anticipated, progress in photovoltaics. The lowest possible measurement uncertainties are required for reliably assessing advances in solar cell technology and reducing investment uncertainty in the growing photovoltaics market. The further reduction of these uncertainties within conventional solar cell measurements is often hindered by the measurement setups themselves. Therefore, innovative concepts and approaches in the development of new measurement facilities are vital.This thesis addresses such demand by applying ultrashort laser pulses for highly accurate solar cell characterization. Based on a detailed investigation of pulse-solar cell interaction, a setup for spectral responsivity measurements is developed. The new setup substantially outperforms current state-of-the-art facilities in terms of measurement accuracy. This cutting-edge measurement setup also allows for establishing further innovative characterization methods such as the ability to measure the quantum efficiency of concentrator photovoltaic modules. Furthermore, a novel measurement approach is presented that takes advantage of spectrally shaped supercontinuum radiation generated from the ultrashort pulses. Imitating standard solar spectra with the shaped supercontinuum radiation promises a quicker and more accurate measurement of the solar cell’s short circuit current than is presently possible using conventional methods.