Perovskite solar module manufacturer Oxford PV announced it achieved a power conversion efficiency of 25.6% for a perovskite-silicon tandem solar module relying on a shingled architecture developed by Germany’s Fraunhofer Institute for Solar Energy Systems (Fraunhofer ISE).

“For the first time, the two organizations have successfully combined Oxford PV’s perovskite-silicon tandem solar cells with Fraunhofer ISE’s Matrix Shingle module technology,” a spokesperson from Oxford PV told pv magazine. “Beyond the efficiency gains, the combination also reduces resistive losses, removes the need for copper interconnects, and improves resilience under partial shading – all key considerations as the industry looks to reduce costs while increasing energy yield.”

The Matrix Shingle approach improves conventional solar module interconnection by replacing traditional busbar-and-ribbon architectures with a dense, overlapping cell layout. In this method, photovoltaic cells are precision-cut into narrow strips and reconfigured into a shingled pattern, similar to roof tiles. Adjacent strips overlap slightly and are bonded using electrically conductive adhesive (ECA), which provides both mechanical adhesion and electrical interconnection between neighboring cell segments.

By eliminating soldered interconnect ribbons and busbars, the architecture removes inactive spacing that would otherwise block incoming light. As a result, optical shading losses are significantly reduced and a larger fraction of the module surface becomes active photovoltaic area, improving packing density. The reduction in metallization shading also enhances current collection efficiency, as more of the cell surface is exposed to sunlight.

In addition, the shingle configuration shortens current pathways and distributes current more uniformly across the module, which can reduce resistive losses and localized heating. The use of ECA instead of high-temperature soldering also reduces thermal stress during assembly, helping to preserve cell integrity and potentially improve long-term reliability. Overall, the Matrix shingle approach increases module power density by combining higher active-area utilization with improved electrical and optical performance.

“We are delighted to be able to combine two high-tech approaches from Europe in this PV module,” said Stefan Glunz, head of photovoltaics at Fraunhofer ISE. “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.”

Two tandem glass-glass modules were built with this configuration and edge sealing to protect the moisture-sensitive solar cells: a 491 W rooftop module with an area of 1.92 m², and a 546 W bifacial module with an area of 2.13 m². “Both achieved an efficiency of 25.6% across the entire module area,” Oxford PV’s spokesperson said.

“Our tandem technology and the shingle interconnection work well together technologically,” said Ed Crossland, chief technology officer at Oxford PV. “Due to the lower current densities of the perovskite–silicon solar cells, they can be cut into wider strips, which increases productivity. Tandem solar cells achieve significantly higher voltages and efficiencies than conventional cells, while the current is lower due to distribution across two sub-cells. This lower current density is beneficial, as it helps reduce resistive losses within the PV module. At the same time, the adhesive interconnection of the Matrix shingle technology is a low-temperature process and requires no copper connectors.”

Oxford PV unveiled its first perovskite-silicon tandem solar module with 26.9% efficiency in June 2024. A few months later, the company announced the commercial launch of perovksite-silicon tandem modules in the United States.

It began working on its perovskite tandem solar modules in 2014 and claims to have a “clear roadmap” to bring the technology to over 30% efficiency.