Spectral Mismatch Correction and Spectrometric Characterization of Monolithic III-V Multi-junction Solar Cells

摘要

III-V monolithic multi-junction (MJ) solar cells reach efficiencies exceeding 30 percent (AM 1.5 global) and have applications in space and in terrestrial concentrator systems. The subcells of monolithic MJ cells are not accessible separately, which presents a challenge to measurement systems and procedures. A mathematical approach is presented which enables a fast way of spectral mismatch correction for MJ cells, thereby significantly reducing the time required for calibration. Moreover a systematic investigation of the I-V parameters of a MJ solar cell with variation of the incident spectrum is possible, herein called 'spectrometric characterization'. This analysis method visualizes the effects of current limitation and shifting of the operating voltage, and yields precise information about the current-matching of the sub-cells. MJ cells can hereby be compared without the need to match the current of the structures to a reference spectrum in advance. Further applications of the spectrometric characterization are suggested, such as for the determination of the radiation response of the subcells of MJ space solar cells or for the prediction of the annual power output of terrestrial MJ concentrator cells.