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).
What’s next?
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 report new methods to improve stability and efficiency of perovskite solar cells
Researchers from Purdue University, University of California and the University of Kentucky have constructed a new perovskite interlayer that reportedly exhibits both superior thermal and moisture stability in ambient conditions.
“Enhancing the stability and lifetime of perovskite devices is necessary in order to realize the goal of commercialization for perovskite photovoltaics,” said Jiaonan Sun. “Today, the stability of commonly used hole transporting layers (HTL) is still a bottleneck for achieving the required lifetime". Poly(triaryl amine) (PTAA) is a promising polymeric hole transporting material used in PSC applications, however, it’s hydrophobicity causes problematic interfacial contact with perovskite, limiting the device’s performance. Led by Dr. Letian Dou, the researchers successfully constructed a uniform two-dimensional (2D) perovskite interlayer with conjugated ligands, between three-dimensional (3D) perovskites and PTAA to improve the power conversion efficiency and the interfacial adhesion of the devices. These increased-ion migration, energy barrier conformal, 2D coated unencapsulated devices with new ligands provide greater thermal and moisture stability in different environments.
Researchers design titanium dioxide sponge to prevent lead leakage in perovskite solar cells
Researchers from CNR-IMM,CNR-IPCB, CNR-NANOTEC, Università Degli Studi di Messina and the University of Basel have shown that lead leakage can be prevented by applying a transparent titanium dioxide (TiO2) sponge in a semitransparent solar cell. The device has demonstrated comparable efficiency to semi-transparent perovskite devices and has an average visible transmittance (AVT) of 31.4%.
The team designed the solar cell for applications such as building-integrated photovoltaics (BIPV) and agrivoltaics, in which the potential lead leakage can be seen as a serious public environmental and health risk source.
Researchers design efficient perovskite solar cell with Mortise-Tenon structure
Researchers from Nanjing Tech University, Wuhan University of Technology and National University of Singapore set out to address two major issues that should be resolved in order to promote perovskite solar cells (PSCs): disorder crystallization of perovskite and unbalanced interface charge extraction, which limit further improvements in device efficiency.
The team used a thermally polymerized additive N-vinyl-2-pyrrolidone (NVP) as a polymer template in the perovskite film, followed by a conventional HTL/Chlorobenzene (CB) solution spin-coating process to remove the residual miscellaneous phases and open the grain boundaries to form monolithic perovskite grains, thereby suppressing the defect-related non-radiative recombination. Furthermore, this process results in the formation of a novel “Mortise-Tenon” (M-T) structure for perovskite/HTL composite film, which provides a larger contact area between perovskite and HTL, thereby facilitating hole extraction to achieve balanced charge management.
Fraunhofer ISE launches two new projects to support the scale-up of perovskite-silicon tandem solar cells
Perovskite-silicon tandem solar cells promise efficiencies of over 30 percent, and it seems that new world efficiency values are reached in an increasing pace. These world records, however, are realized on areas that are about 400 times smaller than the current wafer size of a typical industrial silicon solar cell. Scalability remains a challenge that many solar researchers are trying to overcome, hoping to find promising routes for the scalable and economical production of such solar cells.
In the recently launched research projects "Pero-Si-SCALE" and "LiverPool", funded by the German Federal Ministry for Economic Affairs and Climate Action, the Fraunhofer Institute for Solar Energy Systems ISE is building an independent technology platform for scaling up perovskite-silicon tandem solar cells and modules. The goal is the further development and analysis of cell and module designs as well as manufacturing processes which make a rapid transfer to industry possible.
Researchers demonstrate laser-driven control of fundamental motions of the lead halide perovskite atomic lattice
An international team of scientists from Fritz Haber Institute of the Max Planck Society, École Polytechnique in Paris, Columbia University in New York, and the Free University in Berlin have demonstrated laser-driven control of fundamental motions of the lead halide perovskite (LHP) atomic lattice.
Sketch of the experimental pump-probe configuration. Image from Science Advances
By applying a sudden electric field spike faster than a trillionth of a second (picosecond) in the form of a single light cycle of far-infrared Terahertz radiation, the team unveiled the ultrafast lattice response, which might contribute to a dynamic protection mechanism for electric charges. This precise control over the atomic twist motions could allow to create novel non-equilibrium material properties, potentially providing hints for designing the solar cell material of the future.
Oklahoma State University team selected to receive a $750,000 grant from NASA
A project from Oklahoma State University was selected to receive a $750,000 grant from NASA.
The grant will go toward efforts in exploring a fully Vacuum Thermal Evaporation (VTE)-processed halide perovskite solar cell using only solid precursors for developing a simple solar panel manufacturing process suitable for space.
LONGi announces perovskite/crystalline silicon tandem solar cells with 31.8% efficiency
It was reported that on May 24, at the 16th (2023) International Solar Photovoltaic and Smart Energy (Shanghai) Exhibition (SNEC), LONGi Green Energy Technology announced its “STAR Innovative Ecological Cooperation Platform” and its newly achieved efficiency of 31.8% for perovskite/crystalline silicon tandem solar cells based on commercial CZ silicon wafers.
The German Fraunhofer Institute for Solar Energy Systems (Fraunhofer ISE) reportedly certified LONGi's conversion efficiency of 31.8% for perovskite/crystalline silicon tandem solar cells based on commercial CZ silicon wafers. This was said to be the highest internationally certified conversion efficiency based on the superposition of perovskite on commercial CZ silicon wafers.
FuturaSun acquires perovskite solar startup Solertix
Italian solar company, FuturaSun, has acquired Solertix, a start-up specialized in perovskite solar cell research and upscaling for industrial applications.
This acquisition represents a major investment for FuturaSun in scientific research and in the development of innovative technologies. Alessandro Barin, CEO of FuturaSun, emphasizes the strategic importance of this step, stating, “Perovskite is the future of high-efficiency photovoltaics, and in this specific R&D segment, we couldn’t afford not to be key players, working alongside those who are dedicated to scientific research at the highest academic levels.”
KAUST team announces 33.7% efficiency for perovskite/silicon tandem solar cell
Less than two months after achieving a new world record for tandem solar cell efficiency of 33.2%, KAUST researchers have announced an improvement to this number by reaching a power conversion efficiency of 33.7% for a perovskite-silicon solar cell.
The result was reportedly certified by the European Solar Test Installation (ESTI).
DoE funded project will use PSCs to produce green hydrogen
A Department of Energy (DoE) project, lead by University of Michigan's Prof. Zetian Mi, is using perovskites to develop high efficiency, low cost, and ultrastable production of green hydrogen fuels directly from sunlight and water.
The new method to achieve clean hydrogen through solar water splitting offers a promising path to achieving net-zero carbon emissions. The University of Michigan research team aims to stabilize perovskite-based solar cells to produce highly-efficient, low-cost, ultrastable green hydrogen fuel.