22.8% full-area bifacial n-PERT solar cells with rear side sputtered poly-Si(n) passivating contact

Abstract

High-temperature compatible passivating contacts based on phosphorus doped polysilicon (poly-Si(n)) on a thin silicon oxide, employed on the rear side of bifacial n-PERT like solar cells provide an efficiency increase while being compatible with current photovoltaic manufacturing processes, including the metallization process. However, a simple and cost-effective method for poly-Si(n) deposition is still elusive. Herein, we demonstrate DC-sputtering as a scalable and single side technique for poly-Si(n) manufacturing. First, it is demonstrated how DC-sputtered poly-Si(n) can provide high passivation (iV oc > 730 mV) and low contact resistivity (ρ c < 20 mΩ cm 2 ) when metallized by means of screen printing and firing through of Ag paste. Then, M2-sized bifacial n-PERT solar cells featuring the developed DC sputtered poly-Si(n) at the rear side and a homogenous front side B-emitter reaching a certified efficiency of 22.8% are demonstrated. Quokka simulations based on the developed DC sputtered poly-Si(n) indicate a potential up to 24.8% with an upward potential upon optimization of the front side emitter. This work highlights the feasibility of sputtered poly-Si(n) as an enabler for high-efficiency n-type solar cells. • Ex-situ P-doped PVD sputtered poly-Si passivating contacts integrated in M2 sized bifacial n-PERT solar cells. • M2 bifacial n-PERT devices with 22.8% certified efficiency demonstrated. • Integration of 100 nm of ex-situ doped sputtered poly-Si with screen printing and firing through of Ag paste. • Roadmap toward 25% efficiency presented.