Oxford PV and Fraunhofer ISE have achieved 25.6% module efficiency using perovskite-silicon tandem cells and Matrix Shingle technology
The project produced a 491 W rooftop module and a 546 W bifacial module, both reaching the same efficiency level
Fraunhofer ISE says its Matrix Shingle technology uses lead-free conductive adhesives, reduces copper usage, and improves performance under partial shading
UK’s Oxford PV and Germany’s Fraunhofer Institute for Solar Energy Systems ISE have reported achieving a solar PV module efficiency of 25.6% by combining perovskite-silicon tandem solar cells with shingle architecture.
The Head of Photovoltaics at Fraunhofer ISE Prof. Dr. Stefan Glunz highlights that this module combines 2 high-tech approaches from Europe—Oxford PV’s high-efficiency tandem cells and Fraunhofer ISE’s Matrix Shingle interconnection technology.
“To achieve this, we have cut the solar cells from Oxford PV into shingles, arranged them in a matrix structure, electrically connected them using conductive adhesive, and then encapsulated them,” adds Glunz.
Broadly, the team integrated Oxford PV’s tandem cells into a shingled matrix structure using conductive adhesives, creating glass-glass modules with edge sealing to protect the moisture-sensitive perovskite cells.
With this configuration, they produced a 491 W rooftop module with an area of 1.92 sq. mtr. and a 546 W bifacial module covering 2.13 sq. mtr. Both modules achieved an efficiency of 25.6% across their full area, they claim.
Oxford PV produces its perovskite-silicon solar cells and modules in a pilot manufacturing facility in Brandenburg an der Havel, Germany. It applies perovskite silicon cell onto a silico heterojunction (HJT) solar cell using thin-film processes. Oxford PV’s Chief Technology Officer (CTO) Dr Ed Crossland stressed that due to the lower current density of perovskite silicon cells, these can be cut into wider strips to increase productivity.
According to the duo, the combination of tandem cell technology and shingle interconnection reduces resistive losses, lowers material requirements by eliminating copper connectors, and improves tolerance to partial shading.
The modules were developed under the HoTSun research project, supported by Germany’s Federal Ministry for Economic Affairs and Energy (BMWE). Fraunhofer ISE says the HoTSun project focuses on advancing perovskite-silicon tandem solar cells into industrial-scale PV modules through low-temperature manufacturing methods that reduce stress on the sensitive cells.
Researchers are working on technologies such as conductive polymer bonding, low-temperature soldering, matrix-shingle designs, and glass-glass module structures. The overarching target under the program is to achieve module efficiency exceeding 26%.
The project is also evaluating materials, designs, and production processes, while conducting reliability and climate chamber tests to assess long-term performance and durability.
Earlier in January 2024, both Oxford PV and Fraunhofer ISE announced 25% efficiency for silicon-perovskite tandem solar module, achieving the highest output of 421 W on an area of 1.68 sq. m. (see Fraunhofer ISE & Oxford PV Achieve 25% Tandem Module Efficiency).