PERC-like Si bottom solar cells for industrial perovskite-Si tandem solar cells

This work aims for the development of an industrially feasible Si bottom cell for two-terminal perovskite/Si tandem solar cells. A tunnel oxide and poly-Si based passivating front contact (TOPCon) as a replacement of the phosphorus diffused emitter is investigated to upgrade the industrial PERC technology to tandem bottom solar cells (TOPerc). It is shown that TOPCon is compatible with the temperature budget needed for alloying of the local Al rear contact and provides excellent passivation of the planar surface (iVoc > 720 mV). Different possible process routes and fundamental design constraints like the necessity of a hydrogenation step and a single-sided oxide removal after contact firing were investigated. In a proof-of-concept device low contact resistivity (ρc) and high passivation quality could be transferred from test structures to solar cells. The high open-circuit voltage (Voc) of 691 mV and the low series resistance (Rs) of 0.7 Ωcm2 of such a TOPerc solar cell with TCO interconnection layer highlight the potential of the proposed cell structure.