What are perovskite?
Perovskites are a class of materials that share a similar structure, which display a myriad of exciting properties like superconductivity, magnetoresistance and more. These easily synthesized materials are considered the future of solar cells, as their distinctive structure makes them perfect for enabling low-cost, efficient photovoltaics. They are also predicted to play a role in next-gen electric vehicle batteries, sensors, lasers and much more.
How does the PV market look today?
In general, Photovoltaic (PV) technologies can be viewed as divided into two main categories: wafer-based PV (also called 1st generation PVs) and thin-film cell PVs. Traditional crystalline silicon (c-Si) cells (both single crystalline silicon and multi-crystalline silicon) and gallium arsenide (GaAs) cells belong to the wafer-based PVs, with c-Si cells dominating the current PV market (about 90% market share) and GaAs exhibiting the highest efficiency.
Thin-film cells normally absorb light more efficiently than silicon, allowing the use of extremely thin films. Cadmium telluride (CdTe) technology has been successfully commercialized, with more than 20% cell efficiency and 17.5% module efficiency record and such cells currently hold about 5% of the total market. Other commercial thin-film technologies include hydrogenated amorphous silicon (a-Si:H) and copper indium gallium (di)selenide (CIGS) cells, taking approximately 2% market share each today. Copper zinc tin sulphide technology has been under R&D for years and will probably require some time until actual commercialization.
What is a perovskite solar cell?
An emerging thin-film PV class is being formed, also called 3rd generation PVs, which refers to PVs using technologies that have the potential to overcome current efficiency and performance limits or are based on novel materials. This 3rd generation of PVs includes DSSC, organic photovoltaic (OPV), quantum dot (QD) PV and perovskite PV.
A perovskite solar cell is a type of solar cell which includes a perovskite structured compound, most commonly a hybrid organic-inorganic lead or tin halide-based material, as the light-harvesting active layer. Perovskite materials such as methylammonium lead halides are cheap to produce and relatively simple to manufacture. Perovskites possess intrinsic properties like broad absorption spectrum, fast charge separation, long transport distance of electrons and holes, long carrier separation lifetime, and more, that make them very promising materials for solid-state solar cells.
Perovskite solar cells are, without a doubt, the rising star in the field of photovoltaics. They are causing excitement within the solar power industry with their ability to absorb light across almost all visible wavelengths, exceptional power conversion efficiencies already exceeding 20% in the lab, and relative ease of fabrication. Perovskite solar cells still face several challenge, but much work is put into facing them and some companies, are already talking about commercializing them in the near future.
What are the advantages of Perovskite solar cells?
Put simply, perovskite solar cells aim to increase the efficiency and lower the cost of solar energy. Perovskite PVs indeed hold promise for high efficiencies, as well as low potential material & reduced processing costs. A big advantage perovskite PVs have over conventional solar technology is that they can react to various different wavelengths of light, which lets them convert more of the sunlight that reaches them into electricity.
Moreover, they offer flexibility, semi-transparency, tailored form factors, light-weight and more. Naturally, electronics designers and researchers are certain that such characteristics will open up many more applications for solar cells.
What is holding perovskite PVs back?
Despite its great potential, perovskite solar cell technology is still in the early stages of commercialization compared with other mature solar technologies as there are a number of concerns remaining.
One problem is their overall cost (for several reasons, mainly since currently the most common electrode material in perovskite solar cells is gold), and another is that cheaper perovskite solar cells have a short lifespan. Perovskite PVs also deteriorate rapidly in the presence of moisture and the decay products attack metal electrodes. Heavy encapsulation to protect perovskite can add to the cell cost and weight. Scaling up is another issue - reported high efficiency ratings have been achieved using small cells, which is great for lab testing, but too small to be used in an actual solar panel.
A major issue is toxicity - a substance called PbI is one of the breakdown products of perovskite. This is known to be toxic and there are concerns that it may be carcinogenic (although this is still an unproven point). Also, many perovskite cells use lead, a massive pollutant. Researchers are constantly seeking substitutions, and have already made working cells using tin instead. (with efficiency at only 6%, but improvements will surely follow).
While major challenges indeed exist, perovskite solar cells are still touted as the PV technology of the future, and much development work and research are put into making this a reality. Scientists and companies are working towards increasing efficiency and stability, prolonging lifetime and replacing toxic materials with safer ones. Researchers are also looking at the benefits of combining perovskites with other technologies, like silicon for example, to create what is referred to as “tandem cells”.
Commercial activity in the field of perovskite PV
In September 2015, Australia-based organic PV and perovskite solar cell (PSC) developer Dyesol declared a major breakthrough in perovskite stability for solar applications. Dyesol claims to have made a significant breakthrough on small perovskite solar cells, with “meaningful numbers” of 10% efficient strip cells exhibiting less than 10% relative degradation when exposed to continuous light soaking for over 1000 hours. Dyesol was also awarded a $0.5 million grant from the Australian Renewable Energy Agency (ARENA) to commercialize an innovative, very high efficiency perovskite solar cell.
Also in 2015, Saule Technologies signed an investment deal with Hideo Sawada, a Japanese investment company. Saule aims to combine perovskite solar cells with other currently available products, and this investment agreement came only a year after the company was launched.
In October 2020, Saule launched sunbreaker lamellas equipped with perovskite solar cells. The product is planned to soon be marketed across across Europe and potentially go global after that.
In August 2020, reports out of China suggested that a perovskite photovoltaic cell production line has gone into production in Quzhou, east China's Zhejiang Province. The 40-hectare factory was reportedly funded by Microquanta Semiconductor and expected to produce more than 200,000 square meters of photovoltaic glass before the end of 2020.
In September 2020, Oxford PV's Professor Henry Snaith stated that the Company's perovskite-based solar cells are scheduled to go on sale next year, probably by mid 2021. These will be perovskite solar cells integrated with standard silicon solar cells.
The latest perovskite solar news:
Researchers of Karlsruhe Institute of Technology (KIT) and of two Helmholtz platforms—Helmholtz Imaging at the German Cancer Research Center (DKFZ) and Helmholtz AI—have found a way to predict the quality of the perovskite layers and consequently that of the resulting solar cells. Using machine learning and new methods in artificial intelligence (AI), it is possible to assess their quality from variations in light emission already in the manufacturing process.
"Manufacturing these high-grade, multi-crystalline thin layers without any deficiencies or holes using low-cost and scalable methods is one of the biggest challenges," says tenure-track professor Ulrich W. Paetzold who conducts research at the Institute of Microstructure Technology and the Light Technology Institute of KIT.
Researchers at Northwestern University and University of Toronto have developed a way to improve the efficiency of inverted perovskite solar cell using a combination of molecules to address different issues. They reported a dual-molecule solution to overcoming losses in efficiency as sunlight is converted to energy.
By incorporating a molecule to address surface recombination, in which electrons are lost when they are trapped by defects — missing atoms on the surface, with a second molecule to disrupt recombination at the interface between layers, the team achieved a National Renewable Energy Lab (NREL) certified efficiency of 25.1% where earlier approaches reached efficiencies of just 24.09%.
Researchers from Australia's RMIT University, Monash University, CSIRO Manufacturing, La Trobe University, and Georgia Institute of Technology in the US recently used AI to produce perovskite solar cells in just a matter of weeks, bypassing years of human labor and human error to optimize the cells.
“Until now, the process of creating perovskite cells has been more like alchemy than science – record efficiencies have been reached, but positive results are notoriously difficult to reproduce,” said study lead, author Dr. Nastaran Meftahi from RMIT University’s School of Science. “What we have achieved is the development of a method for rapidly and reproducibly making and testing new solar cells, where each generation learns from and improves upon the previous.”
France-based Armor Group has acquired a 20% stake in French solar module maker HoloSolis.
In 2025, HoloSolis plans to open a TOPCon PV cell and panel factory in France. At full capacity from 2027, the factory is expected to employ 1,700 people and produce 10 million modules per year, for a total capacity of 5 GW per year. HoloSolis is also working on the next generation of solar panels and the perovskite-silicon tandem cells.
Researchers from Nanjing University and University of Electronic Science and Technology of China have designed an all-perovskite tandem solar cell based on a wide bandgap perovskite top cell relying on a two-dimensional/three-dimensional heterostructure and a narrow bandgap bottom cell.
Schematic of the solar cell structure and the corresponding cross-sectional SEM image of an all-perovskite tandem solar cell. Image from Nature Communications
The research group used a generic 3D-to-2D perovskite conversion approach to fabricate the top cell. They first deposited a lead-halide perovskite (methylammonium lead iodide - MAPbI3) layer by a hybrid evaporation/solution method and then transformed the layer into a 2D structure via a long-chain ammonium ligand.
Huasun Energy, China-based developer of HJT solar products, has raised more than RMB2 billion (over USD$275,600,000) in its Series C funding. The lead investor is China Green Development Investment Group (China Green Development), with co-investments from Bank of China Asset Management Co., Ltd. (Bank of China Asset) and China Post Insurance Company Limited (China Post Insurance). Originvest and China Xinxing Asset Management Co., Ltd. (China Xinxing Asset) also increased their investment in this round.
The funding will be used to further expand the production of Huasun's high-efficiency heterojunction (HJT) products and to support the R&D of cutting-edge technologies, including heterojunction-perovskite tandem solar cells.
Researchers at the Chinese Academy of Sciences (CAS), Peking University and Soochow University have developed a polycrystalline silicon tunnelling recombination layer for perovskite/tunnel oxide passivating contact (TOPCon) silicon tandem solar cells (TSCs), which has reportedly achieved excellent efficiency and high stability.
According to the team, previous efforts to increase device efficiency have mainly focused on improving the top sub-cell, leaving much room for improvement. The recombination layer, which serves as the electrical contact between the top and bottom sub-cells, plays a critical role in further efficiency progress. In this study, the researchers developed a polycrystalline silicon (poly-Si) tunnelling recombination layer that was incorporated into a perovskite/TOPCon silicon tandem cell. Through a two-step annealing strategy, the diffusion of boron and phosphorus dopants could be effectively restrained, granting the device excellent passivation and contact performance.
Tokyo Chemical Industry (TCI), a global supplier of laboratory chemicals and specialty materials, is offering a stable supply of high-quality Spiro-OMeTAD hole transport materials, used in perovskite solar panels, light emitting devices and other applications.
Spiro-OMeTAD materials are suitable for solution processing, and feature a HOMO of -5.0 eV and a LUMO of -1.5 eV. This is a standard material used in many perovskite stacks, and is the benchmark material also used in many research activities for comparative evaluation.
TCI has a large-scale capacity to produce this material, in very high quality and at a relatively low cost. See here for more info.
A new project, led by the University of Michigan, could enable industrial competitors to collectively build a predictive model that speeds the development of perovskite solar cells. The aim is to improve upon the process of layer-by-layer deposition of semiconductor materials during production with an information-sharing approach that boosts cooperation between companies while protecting proprietary information and worker interests.
The project is backed by a four-year, $3 million grant from the National Science Foundation and includes partners at the University of California San Diego.
Saule Technologies has announced that yesterday, November 11, the SpaceX Falcon-9 rocket with mission Transporter-9 was launched, carrying its perovskite cells to the Low Earth Orbit.
photo credit: SpaceX and Saule Technologies
Saule Technologies stated that its team has put in immense work researching, developing and creating the perovskite-based PV module adapted for tests in space conditions.