Symmetrical and Crossed Double-Sided Passivation Emitter and Surface Field Solar Cells for Bifacial Applications

Abstract

This paper proposes symmetrical and crossed double-sided passivation emitter and surface field solar cells for bifacial applications which are fully compatible with the passivated emitter and rear contact (PERC) fabrication process. Our simulations use Silvaco TCAD Atlas, calibrated by real measurements. At an ideal albedo level where light enters both sides equally, these symmetrical and crossed structures boost energy by 88.78% and 106.74%, respectively. The reason for the crossed structure’s better performance is that it has a surrounding electric field. The crossed structure also obtains a 40.18 mA/cm2 short-circuit current ( ${J} _{\mathrm{ sc}}$ ), a 0.67 V open-circuit voltage ( ${V} _{\mathrm{ oc}}$ ), an 81.07% fill factor and a 21.93% conversion efficiency ( $\eta $ ). Compared with PERC+, the crossed structure improves low bifaciality factor ( $\varphi _{\eta }$ ) and increases $\eta $ by 6.44% and energy boost by 31.41% for bifacial. For more-realistic albedo levels, the structure also performs strongly. At the spectral albedo level of snow, the energy boost of the crossed structure is 102.06%, which is close to the performance at ideal albedo. At the spectral albedo level of white sand, the energy boost is 77.13%. At lower albedos, the energy boost remains between 20% and 30%.