On Perimeter Losses in Perovskite Top– and Poly–Si–Passivated Silicon Bottom Cells: Do Small Area Tandems Reveal the Full Efficiency Potential?

article

2025

authors
Haase, Felix and Brockmann, Lukas and Raugewitz, Annika and Steckenreiter, Verena and Barnscheidt, Verena and Clausing, Roland and Baumann, Sara and Vollbrecht, Joachim and Veurman, Welmoed and Löhr, Johannes and Liu, Dongyang and Turcu, Mircea and Nasebandt, Lasse and Römer, Udo and Sylla, David and Strey, Jessica and Mettner, Larissa and Winter, Renate and Christ, Anja and Kohlenberg, Heike and Marquardt, Cornelia and Brueckner, Emanuel and Rabiei, Hossein and Rienäcker, Michael and Kajari–Schröder, Sarah and Wietler, Tobias and Peibst, Robby

journal
Solar RRL

doi:10.1002/solr.202500540

abstract

We investigate the perimeter losses in each sub-cell of a small area 2-terminal perovskite-silicon tandem device with poly-Si onoxide based bottom cell passivation. We vary the shaded diode areas by patterning them on the solar cell or using differentaperture masks during J–V measurement. By numerical device simulations, we reveal a perimeter-induced open-circuit voltagereduction from 1912 to 1858 mV for our device geometries of 1 cm2 aperture area on 6.25 cm2-sized silicon bottom cells. Thelargest part of ΔVOC = 26 mV is attributed to recombination in the shaded silicon wafer. A VOC loss of 14 mV is attributed tothe shaded poly-Si diode. The shaded perovskite top cell induces a VOC loss of 14 mV, if the perovskite total area is 1.44 cm2as in our current device. Our so far best in-house measured efficiency is 26.7%. Simulations show, that implementing ourimproved perovskite top cell and front fingers can increase the efficiency by about 2.6%abs. and omitting the perimeter lossesadditional 1.2%abs.. The investigation shows that shading losses are significant and thus have to be taken into account whenexperimentally assessing the efficiency potential of tandem cells on small area devices.