Written on October 12, 2015 by Roni Peleg

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.

Perovskite solar cell market image

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 cell image

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.

Latest Perovskite Solar Cell news

Detection of nanoscale changes in hybrid perovskite crystals may help improve the efficiency of PSCs

Nov 22, 2017

A team of researchers, that includes researchers from the AMOLF Institute in the Netherlands and Argonne National Laboratory and is led by the University of California San Diego, has observed nanoscale changes in hybrid perovskite crystals that could offer new insights into developing low-cost, high-efficiency solar cells.

Using X-ray beams and lasers, the researchers studied how hybrid perovskites behave at the nanoscale level during operation. Their experiments revealed that when voltage is applied, ions migrate within the material, creating regions that are no longer as efficient at converting light to electricity. "Ion migration hurts the performance of the light absorbing material. Limiting it could be a key to improving the quality of these solar cells," said a member of the Sustainable Power and Energy Center at UC San Diego.

Solliance achieves a new efficiency record for perovskite-based PV technology

Nov 22, 2017

Solliance has achieved a new world record for Perovskite Solar Cell technology demonstrated on industrially applicable Roll-to-Roll (R2R) processes of 13.5% conversion efficiency at cell level. The group stressed that the records were achieved in a factory setting, using an industrially scalable process.

Solliance's perovskite pv panel image

Solliance has achieved the conversion efficiency of 13.5% and module-level aperture area conversion efficiency of 12.2% for perovskite-based photovoltaics using industrially-applicable, roll-to-roll production processes. By further optimizing and re-validating processes that were earlier developed buy Solliance, the performance at both the cell and module level have been improved.

Greatcell secures a $825,000 grant for perovskite solar cell commercialization

Nov 19, 2017

Greatcell logo imageGreatcell Solar, developer of solar technologies, was awarded 700,000 euro (about $825 million USD) in a European Union Horizon 2020 project known as Apolo. The grant to Greatcell's application has occurred through its 100% Italian subsidiary, Greatcell Solar Italy located in Rome, that aims to commercialize perovskite solar technology.

Much of the work involved will investigate advanced technology for higher efficiencies, longer life, and improved encapsulation of PSC-enabled flexible substrates, such as metals and polymers. These are all critical in the successful translation of the 3rd generation PSC photovoltaic (PV) technology from the laboratory to the factory and satisfying PV industry accreditation (IEC 61215).

Saule Technologies to demonstrate A4-paper-sized, flexible, printed perovskite solar cells

Nov 12, 2017

Saule Technologies will be presenting a flexible, printed, perovskite photovoltaic module the size of an A4 sheet of paper, for the first time, at the IDTechEx Show on November 15-16th in Santa Clara, CA. The operating Saule module is printed on an ultrathin plastic foil able to charge personal electronic devices, demonstrating one of the many possible applications of these perovskite solar cells. The prototype industry-scale production line is estimated to begin in 2018.

Saule Technologies' flexible perovskite module image

"Scaling up the size of perovskite solar cells is one of the biggest challenges for companies and researchers working with this technology. Printing a stable and operating A4 size module has been among our most important milestones for 2017 and we are more than happy to be able to present it for the first time in the USA," says the CTO and co-founder at Saule Technologies.

EPFL and IPC PAS collaborate to create improved perovskite solar cells via mechanochemistry

Nov 10, 2017

A research team from the Institute of Physical Chemistry of the Polish Academy of Sciences (IPC PAS) in Warsaw and the Ecole Polytechnique Federale de Lausanne (EPFL) in Lausanne (Switzerland), co-operating within the GOTSolar project, has demonstrated a perovskite solar cell with a significantly smaller number of structural defects. The unexpected improvement of the photovoltaic performance was observed when perovskites produced by mechanochemistry were used for the construction of a typical photovoltaic cell.

EPFL IPS mechanochemical process perovskite PVs image

The group from IPC PAS (Warsaw University of Technology) was the first to demonstrate that polycrystalline halide perovskites (CH3NH3)PbI3 can be produced in mechanochemical reactions. Recently, the group presented the mechanochemical production of mixed perovskites, those in which several different types of ions alternate in position A. This is an important achievement, because by carefully altering the chemical composition of the perovskite materials, they can be adapted to specific applications in photovoltaics, catalysis and other fields of science and technology.