Potential of Chemical Rounding for the Performance Enhancement of a Monolithic Perovskite/Bifacial N-PERT Si Tandem Cell

We have investigated the effects of chemical rounding on the performance of bifacial n-PERT Si cells with a random-pyramid textured p
⁺
-emitter. From experimental results, we found that solar-weighted reflectanceR
SW
of pyramid textured p
⁺
-emitters passivated with an ${AlO}_{x}/{SiN}_{x}$:H stack increases and short circuit current densityJ
sc
of bifacial n-PERT Si cells with an ${AlO}_{x}/{SiN}_{x}$:H stack-passivated textured p
⁺
-emitter consequently decreases as a function of chemical rounding time. However, the loss inJ
sc
is fully offset by the increased fill factor FF, and the efficiency of the 200-sec-rounded cells is consequently enhanced, compared to the non-rounded cells. In addition, the deposition of an indium tin oxide layer on the non-rounded and rounded $p^{+}-$ emitters passivated with an ${AlO}_{x}/{SiN}_{x}$:H stack can reduce reflectance largely in the near-infrared region. Based on the experimental results, although we would need further studies, it could be expected that cell efficiency of a bifacial ${n}$-PERT Si bottom cell and its monolithic tandem cell with a perovskite top cell would be improved without additional complicated and costly processes if chemical rounding and boron doping processes are properly optimized.