Rear side dielectrics on interdigitating p ⁺-(i)-n ⁺back-contact solar cells-hydrogenation vs. charge effects

verfasst von

Michael Rienäcker, Yevgeniya Larionova, Jan Krügener, Sascha Wolter, Rolf Brendel, Robby Peibst

Abstract

Polysilicon-on-oxide (POLO) passivating contacts and interdigitated back-contact (IBC) cell technologies have recently attracted a lot of interest as candidates for the implementation in the next generation of solar cells. An IBC cell with POLO junctions for both polarities-a POLO2-IBC cell-has to electrically isolate the highly defective p+ and n+ poly-Si regions on the rear side of the cell to avoid parasitic recombination. Inserting an initially undoped, intrinsic (i) region between the p+ and n+ poly-Si regions was demonstrated to successfully prevent the parasitic recombination in the transition region of ISFH's 26.1%-efficient POLO2-IBC cell. In order to further improve the conversion efficiency towards 27%, we apply hydrogen-donating dielectric layer stacks to the p+-(i)-n+ POLO interdigitating rear side to enhance the passivation quality of the POLO junctions. We indeed show a significant improvement of POLO junctions on symmetrical full-Area homogenously doped reference samples, but when we apply a hydrogen-donating layer stack on the p+-(i)-n+ POLO interdigitating rear side, we observe a strong degradation in the performance of the POLO2-IBC cell. We attribute this to the formation of a conductive channel between the p+ and n+ poly-Si regions due to the strong negative charge density of the hydrogen-donating layer stack.

Organisationseinheit(en)

Institut für Materialien und Bauelemente der Elektronik
Laboratorium für Nano- und Quantenengineering
Abt. Solarenergie

Externe Organisation(en)

Institut für Solarenergieforschung GmbH (ISFH)

Typ

Artikel

Journal

EPJ Photovoltaics

Band

12

Publikationsdatum

09.11.2021

Publikationsstatus

Veröffentlicht

Peer-reviewed

Ja

ASJC Scopus Sachgebiete

Elektronische, optische und magnetische Materialien, Erneuerbare Energien, Nachhaltigkeit und Umwelt, Physik der kondensierten Materie, Elektrotechnik und Elektronik

Ziele für nachhaltige Entwicklung

SDG 7 – Erschwingliche und saubere Energie

Elektronische Version(en)

https://doi.org/10.1051/epjpv/2021007 (Zugang: Offen)