Analysis and optimization of high efficiency multijunction a-Si:H solar cells

摘要

A phenomenological model for multijunction (MJ) a-Si solar cells which integrates a detailed optical model and an equivalent circuit model with voltage-dependent photocurrent was developed. The model has been used to analyze the performance of United Solar's world record stabilized 13.0% efficient triple junction cell. Light-biased MJ quantum efficiency was analyzed to estimate nominal i-layer bandgaps and thickness. Component cell JV data were analyzed to determine a consistent set of i-layer and diode properties. Using the component cell parameters, close agreement was found between the measured and calculated MJ performance. The performance of this MJ cell is insensitive to small changes in the thickness of the i-layers but is sensitive to the /spl mu/t of middle and bottom cells and small changes in bandgap. The model has been combined with a powerful multivariable optimization routine to identify requirements to reach 15% efficiency.