Tandem

Hanwha Solutions Qcells Division (Hanwha Qcells), a global leader in complete clean energy solutions, has announced a new world record, reaching 28.6% for tandem solar cell efficiency on a full-area M10-sized cell that can be scaled for mass manufacturing. This result was achieved despite having only begun large-area tandem development in 2023.

“The tandem cell technology developed at Hanwha Qcells will accelerate the commercialization process of this technology and, ultimately, deliver a great leap forward in photovoltaic performance,” said Danielle Merfeld, Global CTO at Hanwha Qcells. “We are committed to advancing the next generation of solar energy efficiency and will keep investing significantly in research and development to drive progress in this field, as every kilowatt counts on the path to building a more sustainable future.”  

In November 29, Hangzhou Xianna Optoelectronic Technology Co., Ltd. delivered its perovskite α-tandem modules for the China Three Gorges New Energy 50 MW PV demonstration project, in what is said to mark the first commercial application of four-terminal perovskite-silicon tandem modules in China. 

Once the PV power plant utilizing these tandem modules is completed and connected to the local grid, it will significantly alleviate the local grid's supply-demand imbalance, reduce environmental pollution, and improve air quality. The design work for a 500 kW demonstration plant has already been completed, with plans to collaborate with engineering institutes for on-site module layout design. The demonstration plant is expected to be connected to the grid and operational by the end of 2024.

According to reports, China Huaneng (China Huaneng Group Co., Ltd.) has achieved a power conversion efficiency of 26.12% on its self-developed large-size perovskite silicon tandem cell, and the result was certified by a third-party testing institution.

China Huaneng stated that after more than ten years of research, it has established a systematic platform for R&D, pilot testing and analysis of perovskite cells, mastered the technology of large-area high-efficiency perovskite and tandem solar modules, and taken the lead in the application of perovskite photovoltaic technology, carried out the verification of kilowatt-scale solar systems using perovskite modules in various scenarios, and built the first megawatt-scale solar system using large-scale perovskite products in overseas.

Researchers from Huaqiao University, Gold Stone (Fujian) Energy Company, Beijing Huairou Laboratory and Kunshan Shengcheng Photoelectric Technology have reported a four-terminal (4T) perovskite-silicon solar cell with a perovskite-based top cell, with an energy bandgap of 1.67 and lower surface defects. 

Structure of the 4T perovskite/silicon tandem solar cells. Image from Nature Communications

The team integrated a wide-bandgap perovskite solar cell with a hybrid back contact device in a four-terminal tandem cell that achieves high efficiency and stability. The group used a new surface passivation strategy that reportedly helped gain the cell's strong performance.

Over the past five years, six Fraunhofer Institutes combined their expertise in the Fraunhofer lighthouse project "MaNiTU" to identify the most sustainable paths to market of perovskite-silicon tandem solar cells made of stable materials and manufactured using scalable production processes. They were able to show that high cell efficiencies can be achieved using industry-oriented processes, however, they found that such high efficiencies were only currently achievable with lead perovskite materials. Based on these findings, the researchers developed suitable recycling concepts to ensure sustainability.

In the "MaNiTU" project, the Fraunhofer researchers produced new materials with perovskite crystal structures and compared them with existing materials at the cell level. The comparisons showed that high efficiencies can only be achieved with lead perovskites. They then successfully fabricated highly efficient demonstrators, for example, a perovskite silicon tandem solar cell of more than 100 square centimeters with screen-printed metallization and produced mini modules for single and interconnected tandem solar cells. Subsequent life cycle analyses showed that by using suitable production and recycling processes and degradation rates comparable to today's silicon technology, it is feasible to make a sustainable product.

Japan-based startup PXP Corporation, developer of lightweight and flexible solar cells, has raised a total of 1.5 billion yen (almost USD$10 million) in Series A funding, led by SoftBank Corp., with participation from SOLABLE Corporation, Kowa Optronics Co., Ltd., Toyota Tsusho Corporation, J&TC Frontier LLC (a joint investment vehicle between JFE Engineering Corporation and Tokyo Century Corporation), Automobile Fund Co., Ltd., Mitsubishi HC Capital Co., Ltd., Yokohama Capital Co., Ltd., and TARO Ventures. SoftBank has invested approximately 1 billion yen and acquired approximately 29.9% of PXP's shares.

The solar cell technology being developed by PXP has a tandem structure that combines perovskite solar cells and chalcopyrite solar cells, said to achieve more than 1.5 times the energy conversion efficiency (theoretical value: about 42%) of conventional solar cells. In addition, it is lightweight and flexible, weighing about one-tenth of conventional solar cells, and has high durability against shock and vibration. It can be installed in various locations depending on the application, and it is expected to reduce installation costs. PXP and SoftBank aim to use PXP's next-generation solar cells for various purposes, such as operating SoftBank's data center with green energy, in anticipation of future electricity demand.

Researchers from the University of Potsdam and the Chinese Academy of Sciences have combined perovskite with organic absorbers to create highly efficient tandem solar cell. 

The team explained that combining two materials that selectively absorb short and long wavelengths, e.g., blue/green and red/infrared parts of the spectrum, makes the best use of sunlight and is a well-known strategy to increase efficiency in solar cells. Best red/infrared absorbing parts of solar cells so far were, however, made from traditional materials, such as silicon or CIGS (copper indium gallium selenide), which require high processing temperatures, and thus exhibit a relatively high carbon footprint. In their work, the team combined perovskite and organic solar cells, both processed at low temperatures with a low carbon footprint. 

This is a sponsored post by Springer Nature 

Perovskite materials have captured the attention of researchers worldwide due to their remarkable properties and versatile applications. These materials are being extensively studied for use in solar cells, photodetectors, field-effect transistors, light-emitting diodes (LEDs), and spintronics. Perovskites are unique because they offer a combination of high efficiency, low manufacturing costs, and the potential for flexibility and transparency. This makes them highly attractive for various cutting-edge technologies.

Given the relevance of the topic and the growing significance of perovskite materials, Sharon George, Senior Editor, Product Management SpringerMaterials, collaborated with Springer Nature’s blog The Link and interviewed Nature Communications editors to gain some of their insights into Emerging Trends in Perovskite Research - find out more about her findings below.

Image 1: from One-step dual-additive passivated wide-bandgap perovskites to realize 44.72%-efficient indoor photovoltaics, Energy & Environmental Science – https://doi.org/10.1039/D3EE04022D

Advancements in photovoltaics: from tandem to indoor solar cells

Photovoltaics is one of the most hotly discussed topics in perovskite research. According to Natalie Lok Kwan Li (Senior Editor, Nature Communications), current research is heavily focused on improving the performance of solar cells and modules. One of the most exciting advancements in this area is the development of tandem solar cells. These cells combine perovskite materials with other semiconductors to achieve higher efficiencies than traditional single-junction solar cells.

Researchers from South China University of Technology, The Chinese University of Hong Kong, Chinese Academy of Sciences (CAS), National Center for Nanoscience and Technology, Friedrich-Alexander University Erlangen-Nürnberg and Linköping University set out to eliminate deep traps in inorganic narrow bandgap (NBG) perovskites, in order to enable the successful development of 2T inorganic perovskite tandem solar cells (IPTSCs).

The team explained that all-inorganic perovskites prepared by substituting the organic cations (e.g. methylammonium (MA⁺) and formamidinium (FA⁺)) with inorganic cations (e.g. Cs⁺) are effective concepts to enhance the long-term photo- and thermal-stability of perovskite solar cells (PSCs). Hence, inorganic perovskite tandem solar cells (IPTSCs) are promising candidates for breaking the efficiency bottleneck and addressing the stability issue as well. However, challenges in fabricating 2-terminal (2T) IPTSCs due to the inferior film formation and deep trap states induced by tin cations hinder that option. 

The Physikalisch-Technische  Bundesanstalt (PTB), Germany’s national metrology institute, has modernized its solar module calibration system, achieving a measurement uncertainty of just 0.9%—currently the lowest known uncertainty for a power measurement of silicon solar modules under standard test conditions worldwide. 

This achievement was made possible by a new setup based on an LED solar simulator developed by WAVELABS.