On the way to mass production: perovskite silicon tandem cells
The cluster facility operated at HZB allows to produce large-area perovskite/silicon tandem solar cells. This facility, the only one of its kind in the world, helps to develop new industry-related processes, materials and solar cells. © B. Stannowski / HZB
In order to transfer tandem solar cells from laboratory scale to production, HZB is cooperating with the solar module manufacturer Meyer Burger, which has great expertise in heterojunction technology (HJT) for silicon modules. Within the framework of this cooperation, mass production-ready silicon bottom cells based on heterojunction technology are to be combined with a top cell based on perovskite technology.
Meyer Burger is a manufacturer of high-quality solar modules based on silicon heterojunction technology (HJT). Meyer Burger's research and development team has already developed HJT cells in recent years together with Bernd Stannowski's team at the Helmholtz-Zentrum Berlin.
The HZB has great expertise in the field of perovskite solar cells. Recently, laboratory tandem solar cells combining heterojunction and perovskite have achieved record efficiencies of over 31 percent, largely due to the work of Steve Albrecht's group. However, such record-breaking tandem cells have only the laboratory-standard areas of 1 cm² and are partly produced with processes that are not scalable.
"We are therefore delighted to be cooperating with Meyer Burger to transfer this fantastic technology into application," says Bernd Stannowski, who heads the cooperation at HZB. A new cluster facility (KOALA) will also be used. This globally unique facility, funded by the German Federal Ministry of Economics and Climate Protection (BMWK) and the Federal Ministry of Education and Research (BMBF), makes it possible to produce perovskite/silicon tandem solar cells in a vacuum on industry-standard large wafers.
"Meyer Burger manufactures in Europe and thus creates high-quality jobs. In doing so, the company is exploiting technologies that were developed in Europe," says Rutger Schlatmann, director of the Photovoltaics Competence Centre Berlin (PVcomB) at HZB. The new cooperation agreement is set to run for three years.
- CIGS-perovskite tandem cell achieves record efficiency of 25.5 %A Berlin-based team from HZB and Center for the Science of Materials Berlin (CSMB) at the Humboldt-Universität zu Berlin has set a new record for a tandem solar cell. Using a combination of a CIGS semiconductor layer and perovskite, along with several optimised intermediate layers, they were able to convert 25.5% of sunlight into electrical energy. The previous record for this combination of materials and this size of cell stood at 24.6%. The new record has been certified and is visible in the prestigious Solar Cell Efficiency Tables (the "Green Tables"), which serve as the definitive ledger for the global photovoltaic community.
- Disorder creates new properties in compound semiconductorsAn international research team has demonstrated that the intrinsic disorder of the compound semiconductor CuInSnS₄ can be exploited to influence its optical properties. While the atomic vibrations also sense the local disorder, their response is averaged over many different local environments and therefore appear isotropic, as expected for a cubic crystal. In contrast, the optical excitations, known as excitons, are much more sensitive to the local arrangement of atoms. Surprisingly, they show a direction-dependent optical response even though the average crystal structure is cubic. These findings shed new light on the relationship between disorder and material properties, opening up new options for targeted 'disorder engineering' in optoelectronic and photocatalytic devices.
- Perovskite solar cells: Predictions of long-term stabilityReliable statements about the long-term stability of perovskite solar cells are still difficult to make. However, a new study by Dr Carolin Ulbrich’s team, published in the renowned journal Joule, highlights which methods are useful for this purpose and identifies areas where further research is needed.