Recombination Behavior of Photolithography-free Back Junction Back Contact Solar Cells with Carrier-selective Polysilicon on Oxide Junctions for Both Polarities

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• 作者：Michael Rienä ; cker^a ; ^b ; ^{m.rienaecker@isfh.de" class="auth_mail" title="E-mail the corresponding author} ; Agnes Merkle^a ; Udo Rö ; mer^a ; Heike Kohlenberg^a ; ^b ; Jan Krü ; gener^b ; ^c ; Rolf Brendel^a ; ^d ; Robby Peibst^a ; ^c
• 关键词：back junction back contact solar cell ; polysilicon on oxide junctions ; POLO ; pn junction ; trench isolation ; recombination
• 刊名：Energy Procedia
• 出版年：2016
• 出版时间：August 2016
• 年：2016
• 卷：92
• 期：Complete
• 页码：412-418
• 全文大小：725 K

文摘

We report on ion-implanted, inkjet patterned back junction back contact silicon solar cells with POLysilicon on Oxide (POLO) junctions for both polarities – n⁺ doped BSF and p⁺ doped emitter. The recombination behavior is investigated at two different processing stages: before and after trench separation of p⁺ and n⁺ regions within polysilicon (poly-Si). Before trench separation, we find a systematic dependence of the recombination behavior on the BSF index, i.e. the p⁺n⁺-junction meander length in the poly-Si. Obviously, recombination at the p⁺n⁺-junction in the poly-Si limits the implied open circuit voltage V_oc,impl. at one sun illumination and the implied pseudo fill factor pFF_impl. to 695 mV and 80%, respectively. After trench isolation, however, V_oc,impl (pFF_impl.) values increase up to 730 mV (85.5%), corresponding to a pseudo-efficiency of 26.2% for an assumed short circuit current density J_sc of 42 mA/cm². We demonstrate a photolithography-free back junction back contacted solar cell with p-type and n-type POLO junctions with an in-house measured champion efficiency of 23.9% on a designated area of 3.97 cm². This efficiency is mainly limited by the imperfect passivation in the undoped trench regions and at the undoped front side.