Krauß, KarinKarinKraußFertig, FabianFabianFertigGreulich, Johannes M.Johannes M.GreulichClement, FlorianFlorianClementBiro, DanielDanielBiroPreu, RalfRalfPreuRein, StefanStefanRein2022-03-122022-03-122014https://publica.fraunhofer.de/handle/publica/38547310.4229/EUPVSEC20142014-2CV.4.11The recently introduced BOSCO (""Both Sides Collecting and Contacted"") solar cell exhibits emitter regions on front and rear side, which are interconnected by diffused vias. This allows double-sided collection of carriers in the base and bifacial operation while supporting standard module interconnection technology. Since the BOSCO cell's rear side exhibits p-doped as well as highly n+-doped surfaces the dielectric used as rear-side passivation needs to be suitable to passivate both polarities. This work compares the passivation of the BOSCO cell's rear side by a PECVD aluminium oxide (AlOx) and a thermally grown silicon oxide (SiO2). A difference in efficiency of up to = 0.5 %abs occurs between BOSCO cells with AlOx and SiO2 passivation, with the AlOx passivated solar cells achieving better cell performance. The difference in efficiency is dominated by a loss in fill factor of up to FF = 1.6 %abs for cells with SiO2 passivation compared to AlOx passivated cells. An investigation of the suns-Voc characteristics shows that this loss is mainly caused by increased recombination at lower injection, which strongly affects the pseudo fill factor. This work shows that the choice of rear-side passivation is essential to optimize the performance of BOSCO solar cells.enPV Produktionstechnologie und QualitätssicherungSilicium-PhotovoltaikMesstechnik und ProduktionskontrolleBOSCObifacialdouble-sided collectionsiliconconference paper