By Wei Shan, Chief Scientist and Head of R&D., JA Solar Holdings Co. Ltd, JA Solar USA; Xiulin Jiang, R&D Center, JA Solar Holdings Co. Ltd.; Haibin Yu, R&D Center, JA Solar Holdings Co. Ltd.; Yong Liu, Chief Operations Officer, R&D Center, JA Solar Holdings Co. Ltd.
A recent revitalization of the passivated emitter and rear cell (PERC) concept in the silicon PV industry has resulted in solar energy conversion efficiencies of greater than 20% being achieved on p-type solargrade single-crystalline silicon (mono-Si) wafers during the past two years or so, thanks to technological advance in the use of aluminium oxide for silicon surface passivation. The research efforts carried out at JA Solar in developing an industry version of PERC cells that can be mass produced utilizing the existing conventional back-surface field (BSF) cell manufacturing platform with moderate retrofitting have yielded 20.5% average conversion efficiency, which can be consistently achieved on p-type Si wafers grown by the Czochralski method. Moreover, the experimental results showed that an average conversion efficiency of 20% is achievable when, in combination with JA Solar’s proprietary light-trapping technique, the same technological approach is applied to the cells using high-quality polycrystalline silicon (multi-Si) wafers produced by the seeded directional solidification method.
