Tandem - Page 15

Researchers taking part in the EU project PERCISTAND, among them ones from the Karlsruhe Institute of Technology (KIT) and TNO, have developed perovskite/CIS tandem solar cells with an efficiency of almost 25% – the highest for this technology to date.

In addition, this combination of materials reportedly ensures lightness and versatility, so that the use of these tandem solar cells on vehicles, portable devices and foldable or rollable devices is also conceivable. 

Scientists at the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL), CU-Boulder and the University of Toledo have demonstrated a tin-lead perovskite cell that overcomes problems with stability and improves efficiency. The new cell, a tandem design with two layers of perovskites, reached 25.5% efficiency.

The new cell also retained 80% of its maximum efficiency after 1,500 hours of continuous operation, or more than 62 days.

Recent reports claim that South Korea's Hyundai auto group has teamed up with a research team at Ulsan National Institute of Science and Technology (UNIST) to develop new perovskite solar cells that can charge vehicles while they are under the sun. 

Hyundai Motor already released solar roofs with silicon solar panels, but their acceptance has been slow without improvements in weight and efficiency, as silicon solar cells are quite heavy and have technical limitations in improving efficiency. In a recent ceremony, the Ulsan National Institute of Science and Technology (UNIST) opened a joint laboratory with Hyundai to develop high-efficiency, large-area perovskite-silicon tandem cells and apply them to solar roofs. The joint laboratory will operate for three years until May 2025.

EPFL scientists in Neuchâtel have reported a tandem solar cell that can deliver a certified efficiency of 29.2%. This achievement was made possible by combining a perovskite solar cell with a textured silicon solar cell.

One obstacle the team encountered was finding a way to evenly coat the silicon surface'which is intentionally rough, or textured'with a thin film of halide perovskites. A textured surface is used in order to minimize light reflection. This kind of system can already be found in all commercially available crystalline silicon cells.

A group of scientists from the University of Wuppertal, the University of Tübingen, the University of Potsdam, HZB, Max Planck Institute and the University of Cologne in Germany recently developed a perovskite-organic tandem solar cell with optimized charge extraction, a high open-circuit voltage and a thickness of just 1 µm.

The tandem configuration includes a narrow-bandgap organic subcell with a p-i-n-type architecture based on the polymer PM6 and molybdenum oxide (MoOx) as the hole extraction layer (HEL). The cell has a power conversion efficiency of 17.5%, an open-circuit voltage of 0.87 V, a short-circuit current of 26.7 mA cm'², and a fill factor of 75%. The wide-bandgap perovskite subcell was built with a perovskite known as FA_0.8Cs_0.2Pb(I_0.5Br_0.5)₃, with an efficiency of 16.8%, an open-circuit voltage of 1.34 V, a short-circuit current of 15.6 mA cm'², and a fill factor of 81%.

The Centre for Solar Energy and Hydrogen Research Baden-Württemberg (ZSW), aiming to fast-track tandem solar technology's time to market, has put two new high-performance coating plants into operation.

The systems produce tandem solar cells consisting of a perovskite solar cell that can be combined with other types of solar cells. The various layers are deposited under ultra-clean conditions. Companies in the solar sector can take advantage of these capabilities to optimize their developments in the area of tandem solar cells.

The European Commission has recently given the green light to an agreement to finance the NEXUS project, focused on the development of innovative processes for TANGO HJT/Perovskite technology for the production of sustainable and high-performance photovoltaic modules.

Coordinated by the University of Oxford, the NEXUS project is supported by a multidisciplinary consortium with 12 partners from 9 European countries; 5 industrial partners, including 2 small and medium-sized enterprises (SMEs); and 7 research and technology organizations.

Chinese company Golden Solar has signed an agreement with two partners to pursue commercial production of perovskite tandem solar cells with 'more than 28%' conversion efficiency.

The Chinese company, which has extremely varied areas of business, is focusing on HJT manufacturing and will combine its solar wafer and HJT technology with the HJT expertise of solar manufacturer Gold Stone (Fujian) Energy Co. Ltd. It will also draw upon the perovskite and tandem knowledge of the National University of Singapore's Solar Energy Research Institute of Singapore.

Researchers from solar manufacturer Hanwha Q CELLS and research institute Helmholtz-Zentrum Berlin (HZB) have announced a power conversion efficiency of 28.7% for a two-terminal perovskite-silicon tandem solar cell.

The device is based on a silicon bottom cell relying on Hanwha Q CELLS' monocrystalline Q.antum half cell technology and a perovskite-based top cell.

Researchers from Germany's Helmholtz-Zentrum Berlin (HZB) and Institute for Solar Energy Research (ISFH) have reported that passivated emitter and rear cell (PERC) tech can be suitable as a basis for tandem cells with perovskite top cells.

PERC cells are usually used in mass production of silicon solar cells, and while the efficiency of the study's tandem cells is still below that of optimized PERC cells alone, the team estimates that it could be increased to up to 29.5% through targeted optimization.