Progress in emitter wrap-through solar cell fabrication on boron doped Czochralski-grown silicon

authored by: Sonja Hermann, Agnes Merkle, Christian Ulzhfer, Silke Dorn, Ilka Feilhaber, Miriam Berger, Thomas Friedrich, Till Brendemhl, Nils Peter Harder, Lotte Ehlers, Katrin Weise, Rüdiger Meyer, Rolf Brendel
Abstract: We report on RISE-EWT (Rear Interdigitated Single Evaporation-Emitter Wrap-Through) solar cells on full area (12.5×12.5 cm²) pseudo square boron doped Czochralski-grown silicon wafers. We investigate the main efficiency optimisation factors of these cells by investigating the dependence of RISE-EWT cell parameters on the base dopant concentration N_A. We furthermore detail the effects of large feature sizes in base and emitter regions at the rear of the solar cell and investigate these effects with particular attention to the edge regions. EWT solar cells typically exhibit rather low fill factors. However, our results show that the improved fill factors can be achieved by increasing N_A, which in return leads to optimised efficiency values. For our RISE-EWT solar cells made from boron doped Cz-Si wafers, this benefit is maintained even after light-induced degradation. Our investigation of edge area related effects shows the importance of proper cell design in these areas, leading to a further 2.8% absolute improvement in the fill factor. Combining increased base dopant concentration with optimised edge design, we achieve 19.0% efficiency on (12.5×12.5 cm²) boron doped Cz silicon wafers before light-induced degradation, resulting in 18.1% efficiency in the light-degraded state.
Organisation(s): Institute of Solid State Physics
External Organisation(s): Institute for Solar Energy Research (ISFH)
STIEBEL ELTRON GmbH & Co. KG
Type: Article
Journal: Solar Energy Materials and Solar Cells
Volume: 95
Pages: 1069-1075
No. of pages: 7
ISSN: 0927-0248
Publication date: 04.2011
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Renewable Energy, Sustainability and the Environment, Surfaces, Coatings and Films
Sustainable Development Goals: SDG 7 - Affordable and Clean Energy
Electronic version(s): https://doi.org/10.1016/j.solmat.2010.12.004 (Access: Closed)