Oxford PV

A group of scientists from Germany's Fraunhofer Institute for Solar Energy Systems (Fraunhofer ISE), with support from Oxford PV Germany, have examined shingling as an interconnection method for perovskite-silicon tandem (PVST) cells.

Full-format perovskite-silicon tandem shingle modules produced at Fraunhofer ISE in collaboration with Oxford PV. Image from Solar Energy Materials and Solar Cells.

The scientists explained that the combination of PVST cells with shingling allows boosting the module efficiency even further due to the increase of the photoactive area through the absence of cell gaps. They went on to say that shingling suits the temperature limitations of the PVST cells since the main factor for the choice of the processing temperature is the curing conditions of the electrically conductive adhesive.

Oxford PV has announced that its perovskite-on-silicon tandem solar cells will be deployed for the first time on the race car of the Top Dutch Solar Racing team for the upcoming Bridgestone World Solar Challenge. 

Taking place between the 22nd and 29th of October 2023, the competition brings some of the world’s greatest scientific and engineering talent to Australia to travel 3,000 kilometers in a vehicle powered only by the energy of the sun. University-affiliated teams push the limits of technological innovation and travel the outback in solar-powered vehicles that they have designed, engineered and ultimately built themselves.

Researchers from the Fraunhofer Institute for Solar Energy Systems (Fraunhofer ISE) and Oxford PV Germany have developed low temperature manufacturing processes for perovskite silicon tandem cells and heterojunction solar cells. The novel techniques are reportedly able to reduce silver consumption and avoid lead-containing soldering materials.

The scientists developed two different processes: front-side metallization at very low temperatures for full-size perovskite silicon tandem solar cells; and the interconnection to high-efficiency full-format demonstrator modules with an output power of more than 400 W.

Oxford PV has announced 'a new world record for the efficiency of a commercial-sized solar cell'. The efficiency record was achieved on a commercial-sized ‘M4’ (258.15 cm²) solar cell. The cell is a 2T device made by depositing a perovskite thin-film cell onto a conventional silicon heterojunction cell.

The record-breaking solar cell converted 28.6% of the sun’s energy into electricity, as independently certified by Fraunhofer ISE. The solar cell was produced at Oxford PV’s integrated production line in Brandenburg an der Havel, Germany. The factory has commenced initial production of the company’s tandem solar cells for integration by solar module manufacturing partners and is ramping up to higher volumes. The site, operational since 2017, houses the world’s first volume manufacturing line for perovskite-on-silicon tandem solar cells.

To pave the way for the industrial implementation of efficient perovskite-silicon PV modules, a reliable measuring system for tandem solar cells and modules must be established. Only then can objective comparisons between different cells and modules take place. In contrast to conventional silicon PV modules, however, the calibration is considerably more challenging. 

A project consortium, led by the Fraunhofer Institute for Solar Energy Systems ISE, is therefore developing methods for characterizing perovskite-based tandem modules in the "Katana" project, funded by the German Federal Ministry for Economic Affairs and Climate BMWK. The solar simulator specially built for this purpose by the company Wavelabs Solar Metrology Systems GmbH is now in use in the CalLab PV Modules of the research institute.

A UK-based quantum software company called Phasecraft will lead a project modelling new perovskite-silicon materials for solar photovoltaics. The project, in collaboration with Oxford PV and scientists at University College London (UCL), is aimed to support the development of quantum computing to simulate “currently intractable problems” in PV materials modelling, according to a recent statement.

Not many details were given regarding the new project, which received an award from UK Research and Innovation’s Commercializing Quantum Technologies Challenge. It was, however, said that it will set out to develop a modelling capability that is tailored to the real-world needs of the PV industry.

A team of scientists from Technische Universität Berlin, Oxford PV Germany, German Philipps-Universität Marburg, Helmholtz Zentrum Berlin (HZB) and Oxford PV UK has, for the first time, assessed the environmental performance of industrially produced perovskite-on-silicon PV modules. Understanding the environmental impact of solar PV modules across their entire lifecycle is essential for the design of more sustainable solar energy systems. However, lifecycle assessment of perovskite-on-silicon PV modules has so far relied heavily on data from laboratory and test facilities rather than manufacturers.

The researchers conducted a comprehensive lifecycle assessment of a perovskite-on-silicon module across a number of categories including global warming potential, water consumption, human and marine toxicity, and metals usage. They assessed the materials and energy input for a module’s ‘cradle to gate’ lifecycle, covering all materials and energy input for wafer production, manufacture of the perovskite cell, and module production. The researchers then weighed up the environmental impact of the tandem module against the electricity generated over its lifetime.

Perovskite solar panels have been under intensive R&D, and it seems as if commercial production is right around the corner. Some pilot-scale production lines are already functional, and companies are now ramping up production of perovskite panels, using various technologies.

UK-based Oxford PV, for example, recently announced that it has completed the build-out of its 100 MW manufacturing site in Germany, and it is on track to start full production in 2022. China's Microquanta Semiconductor perovskite panel factory is reportedly also nearing production (which should have started late 2020, but updates have not been available since), and another China-based company, GCL, has raised around $15 million USD to expand its pilot-scale production factory to mass production (100 MW).

Scientists from Oxford PV have recently published a study describing how pairing metal halide perovskites with conventional silicon leads to a more powerful solar cell that overcomes the 26% practical efficiency limit of using silicon cells alone.

'We identified perovskites as the perfect partner for a tandem system with silicon,' commented author Laura Miranda Pérez.

Solar panel developer and producer Meyer Burger says it is pursuing new research projects on the industrialization of perovskite solar cells. The company is aiming to partner with research institutes worldwide for perovskite technologies.

Meyer Burger also updated that an "extensive industrial research project" is already underway with the Fraunhofer Institute in Germany.