ALUMINIUM-DOPED P~+ SILICON FOR REAR EMITTERS AND BACK SURFACE FIELDS: RESULTS AND POTENTIALS OF INDUSTRIAL N- AND P-TYPE SOLAR CELLS

摘要

We compare identically processed n- and p-type silicon solar cells with each other featuring aluminium-doped p~＋ regions on the rear made from screen-printed paste and acting as emitter or back surface field, respectively. We investigate near-industrial large-area n~+np~+ rear junction and n~＋pp~＋ front junction cells and discuss three cell concepts with different rear side structures: (i) For solar cells with a full-area non-passivated Al-p~＋ rear, we demonstrate similar performances on n- and p-type float-zone Si material with efficiencies of 18.6% and 18.4%, respectively. For our best n-type cell with a rear Al emitter coverage of 100%, we have achieved a record-high efficiency of 19.3%. (ii) For solar cells with a full-area and surface-passivated Al-p+ rear, we have obtained an increase in the open-circuit voltage of 10 mV and in the short-circuit current density of 1.5 mA/cm~2. (iii) For solar cells with laser-fired Al-p~＋ points in the passivated rear Si surface, we have reached an efficiency of 19.6% for a p-type LFC cell.