20%-Efficient TOPCon Solar Cell with a Silicon Oxide Layer Deposited by Aerosol Impaction-Driven Assembly

Tunnel oxide passivated contacts (TOPCon) have become an increasingly popular contact choice for use in silicon solar cells due to their carrier-selective capabilities and success in creating high-efficiency devices. TOPCon structures, fabricated using a thin silicon oxide (SiOx) passivation layer topped with a layer of doped polysilicon (poly-Si) have enabled cell efficiencies higher than 25%. In this work, we explore the use of a TOPCon rear contact-paired with a standard silicon heterojunction (SHJ) front contact to create hybrid cells-utilizing a novel oxide deposition technique, aerosol-impaction-driven assembly (AIDA). The best cells exceed 20% efficiency and are limited by the processing (in)compatibility of the TOPCon and SHJ contacts. Unusually for TOPCon, we find that AIDA oxide layers up to 6 nm thick provide both decent passivation and sufficient conduction pathways to produce cells with >75% fill factor, indicating a non-tunneling conduction mechanism.