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:
A research group led by Prof. LIU Shengzhong from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) has reported the fabrication of high efficiency large-area perovskite solar module using slot-die coating with high-pressure nitrogen-extraction (HPNE) and effective passivation strategy.
Slot-die coating is a promising deposition technique due to its advantages in low cost, high throughput, continuous roll-to-roll fabrication. However, it remains a challenge to control thin film uniformity over a large area at thickness as thin as 500 nm while maintaining crystallization quality.
Florida State University team deepens understanding of perovskite degradation mechanisms to improve stability of solar cells
Florida State University (FSU) researchers are working to better understand the fundamental processes in perovskites. As art of this task, they found that small tweaks to the chemical makeup of the materials as well as the magnitude of the electrical field it is exposed to can greatly affect the overall material stability.
"How can we make perovskites more stable under real-world conditions in which they'll be used?" FSU Assistant Professor of Chemistry and Biochemistry Lea Nienhaus said. "What is causing the degradation? That's what we're trying to understand. Perovskites that don't degrade quickly could be a valuable tool for obtaining more energy from solar cells."
Researchers at Monash University, University of Sydney and University of Melbourne in Australia have addressed a fundamental challenge standing before massive commercialization of perovskite solar cells - light-induced phase segregation, in which illumination, such as sunlight, disrupts the carefully arranged composition of elements within mixed-halide perovskites.
Light-induced segregation often leads to instability in the material’s bandgap, interfering with the wavelengths of light absorbed, while reducing charge-carrier conduction and the efficiency of devices.
Scientists at the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) have reported a breakthrough in the development of a next-generation thermochromic window that not only reduces the need for air conditioning but simultaneously generates electricity.
The technology, dubbed “thermochromic photovoltaic,” allows the window to change color to block glare and reduce unwanted solar heating when the glass gets warm on a sunny day. This color change also leads to the formation of a functioning solar cell that generates on-board power. Thermochromic photovoltaic windows can help buildings turn into energy generators, increasing their contribution to the broader energy grid’s needs. The newest breakthrough now enables various colors and a broader range of temperatures that drive the color switch. This increases design flexibility for improving energy efficiency as well as control over building aesthetics that is highly desirable for both architects and end users.
Poland-based Saule Technologies that develops flexible photovoltaic cells based on perovskite technology, recently launched sunbreaker lamellas equipped with perovskite solar cells. In a market full of potential and promises but still low on commercial products, it is definitely encouraging to see the launch of a product such as this.
The product presentation took place in cooperation with partners Somfy and Aliplast. The company intends to commercialize the sunbreakers in cooperation with the company to be selected in a tender. The first presentation of the product took place at Silesia Ring track during an event attended by representatives of the management of several dozen of the largest Polish companies from such industries as logistics, retail, FMCG, telecommunications and real estate. The product presented during the premiere included an automation system and smart cover control by Somfy, and an aluminum construction provided by Aliplast.