VIRE-EFFECT: VIA-RESISTANCE INDUCED RECOMBINATION ENHANCEMENT - THE ORIGIN OF REDUCED FILL FACTORS OF EMITTER WRAP THROUGH SOLAR CELLS

摘要

Emitter wrap through solar cells (EWT) are known for exhibiting low fill factors (FF). In this contribution we explain the FF losses by a three-dimensional EWT simulation model. The origin of reduced FF of EWT solar cells can be explained by Via-resistance Induced Recombination Enhancement (VIRE-effect). A voltage drop along the EWT-via emitter enhances the injection of minority carriers at the front pn-junction which causes higher recombination currents compared to those at the rear pn-junction. We explain the principle how the VIRE-effect leads to a deformation of the I-V characteristics and discuss its influence by showing 3d-simulation regimes.