Evaluation of advanced p‐PERL and n‐PERT large area silicon solar cells with 20.5% energy conversion efficiencies

Abstract

AbstractIn this paper, we evaluate p‐type passivated emitter and rear locally diffused (p‐PERL) and n‐type passivated emitter and rear totally diffused (n‐PERT) large area silicon solar cells featuring nickel/copper/silver (Ni/Cu/Ag) plated front side contacts. By using front emitter p‐PERL and rear emitter n‐PERT, both cell structures can be produced with only a few adaptations in the entire process sequence because both feature the same front side design: homogeneous n+ diffused region with low surface concentration, SiO2/SiNx:H passivation, Ni/Cu/Ag plated contacts. Energy conversion efficiencies up to 20.5% (externally confirmed at FhG‐ISE Callab) are presented for both cell structures on large area cells together with power‐loss analysis and potential efficiency improvements based on PC1D simulations. We demonstrate that the use of a rear emitter n‐PERT cell design with Ni/Cu/Ag plated front side contacts enables to reach open‐circuit voltage values up to 676 mV on 1–2 Ω cm n‐type CZ Si. We show that rear emitter n‐PERT cells present the potential for energy conversion efficiencies above 21.5% together with a strong tolerance to wafer thickness and bulk resistivity. Copyright © 2014 John Wiley & Sons, Ltd.