Towards 20% efficient large-area screen-printed rear-passivated silicon solar cells

authored by: Thorsten Dullweber, Sebastian Gatz, Helge Hannebauer, Tom Falcon, Rene Hesse, Jan Schmidt, Rolf Brendel
Abstract: We have implemented a baseline solar cell process based on today's standard industrially manufactured silicon solar cells. Using this process, we achieve conversion efficiencies up to 18.5% applying 125 × 125 mm pseudo-square p-type 2-3 Ω cm boron-doped Czochralski silicon wafers featuring screen-printed front and rear contacts and a homogenously doped 70 Ω/n⁺-emitter. Optimizing a print-on-print process for the silver front side metallization, we reduce the finger width from 110 to 70 μm, which increases the conversion efficiency up to 18.9% due to the reduced shadowing loss. In order to further increase the efficiency, we implement two different dielectric rear surface passivation stacks: (i) a silicon dioxide/silicon nitride stack and (ii) an aluminium oxide/silicon nitride stack. The rear contacts to the silicon base are formed by local laser ablation of the passivation stack and aluminium screen printing. The dielectric layer stacks at the rear decrease the surface recombination velocity from S_eff,rear = 350 cm/s for a full-area Al back surface field down to S_eff,rear = 70 cm/s and increase the internal reflectance from 61% up to 91%. The improved solar cell rear increases the conversion efficiency Î· up to an independently confirmed value of 19.4%, the short-circuit current density J _sc up to 38.9 mA/cm and the open-circuit voltage V_oc up to 662 mV. The detailed solar cell analysis reveals potential to further increase the conversion efficiency towards 20% in the near future.
Organisation(s): Solar Energy Section
External Organisation(s): Institute for Solar Energy Research (ISFH)
DEK Printing Solutions (ASMPT)
Type: Article
Journal: Progress in Photovoltaics: Research and Applications
Volume: 20
Pages: 630-638
No. of pages: 9
ISSN: 1062-7995
Publication date: 09.2012
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Renewable Energy, Sustainability and the Environment, Condensed Matter Physics, Electrical and Electronic Engineering
Sustainable Development Goals: SDG 7 - Affordable and Clean Energy
Electronic version(s): https://doi.org/10.1002/pip.1198 (Access: Unknown)