HZB Sets New World Record for CIGS Perovskite Tandem Solar Cells
© G. Farias Basulto / HZB
The tandem cell consists of a combination of CIGS and perovskite and achieves a certified record efficiency of 24.6%. © G. Farias Basulto / HZB
The main components are clearly visible under the scanning electron microscope: granular CIGS crystals on the contact layer, followed by an intermediate layer of aluminium-doped zinc oxide, above which is the extremely thin perovskite layer (black). This is followed by an indium-doped zinc oxide layer and an anti-reflective coating. © HZB
Combining two semiconductor thin films into a tandem solar cell can achieve high efficiencies with a minimal environmental footprint. Teams from HZB and Humboldt University Berlin have now presented a CIGS-perovskite tandem cell that sets a new world record with an efficiency of 24.6%, certified by the independent Fraunhofer Institute for Solar Energy Systems.
Thin-film solar cells require little energy and material to produce and therefore have a very small environmental footprint. In addition to the well-known and market-leading silicon solar cells, there are also thin-film solar cells, e.g. based on copper, indium, gallium and selenium, known as CIGS cells. CIGS thin films can even be applied to flexible substrates.
Now, experts from HZB and Humboldt University Berlin, have developed a new tandem solar cell that combines a bottom cell made of CIGS with a top cell based on perovskite. By improving the contact layers between the top and bottom cells, they were able to increase the efficiency to 24.6 %. This is the current world record, as certified by the Fraunhofer Institute for Solar Energy Systems ISE in Freiburg, Germany.
As always, this record cell was the result of a successful team effort: the top cell was fabricated by TU Berlin master's student Thede Mehlhop under the supervision of Stefan Gall. The perovskite absorber layer was produced in the joint laboratory of HZB and Humboldt University of Berlin. The CIGS sub-cell and contact layers were fabricated by HZB researcher Guillermo Farias Basulto. He also used the high-performance cluster system KOALA, which enables the deposition of perovskites and contact layers in vacuum at HZB.
‘At HZB, we have highly specialised laboratories and experts who are top performers in their fields. With this world record tandem cell, they have once again shown how fruitfully they work together,' says Prof. Rutger Schlatmann, spokesman for the Solar Energy Department at HZB.
The record announced today is not the first world record at HZB: HZB teams have already achieved world record values for tandem solar cells several times, most recently for silicon-perovskite tandem solar cells, but also with the combination CIGS-perovskite.
We are confident that CIGS-perovskite tandem cells can achieve much higher efficiencies, probably more than 30%," says Prof. Rutger Schlatmann.
- Optical innovations for solar modules - which are the most promising?In 2023, photovoltaic systems generated more than 5% of the world’s electrical energy and the installed capacity doubles every two to three years. Optical technologies can further increase the efficiency of solar modules and open up new applications, such as coloured solar modules for facades. Now, 27 experts provide a comprehensive overview of the state of research and assess the most promising innovations. The report, which is also of interest to stakeholders in funding and science management, was coordinated by HZB scientists Prof. Christiane Becker and Dr. Klaus Jäger.
- Catalysis research with the X-ray microscope at BESSY IIContrary to what we learned at school, some catalysts do change during the reaction: for example, certain electrocatalysts can change their structure and composition during the reaction when an electric field is applied. The X-ray microscope TXM at BESSY II in Berlin is a unique tool for studying such changes in detail. The results help to develop innovative catalysts for a wide range of applications. One example was recently published in Nature Materials. It involved the synthesis of ammonia from waste nitrates.
- Samira Aden joins ETIP PV - The European Technology & Innovation Platform for Photovoltaics ESG Working GroupSamira Jama Aden, Architect Design Research, has joined the ETIP PV - The European Technology & Innovation Platform for Photovoltaics working group “Environmental, Social and Governance (ESG)”.