Researchers examine the heat capacity of perovskite solar cells


Renewable technologies, such as solar and wind power, are major areas of focus for research, as environmental protection and global renewable energy trends influence how humans approach strategies. energies towards a green and peaceful future for the planet.

From left to right: Dr Esma Ugur, Dr Randi Azmi, Prof. Stefan De Wolf and Dr Akmaral Seitkhan. Image credit: King Abdullah University of Science and Technology.

The emerging field of perovskite solar cells (PSC) has gained popularity in the solar technology industry over the past decade and a half for providing excellent power conversation efficiencies (PCE).

However, in a market dominated by silicon solar cells, the fairly modern technology must also meet two other requirements for commercialization: stability and scalability.

The first successful evaluation of PSC photovoltaic (PV) damp heat by KAUST researchers marked a major milestone. The study was published in the Science newspaper.

The damp heat test is an accelerated and rigorous environmental weathering test designed to determine the ability of solar panels to withstand sustained exposure to high moisture penetration and high temperatures. The test is performed for 1000 hours in a controlled environment with 85% humidity and 85°C temperature. It is designed to simulate several years of outdoor exposure and assess aspects such as corrosion and delamination.

Pass the test

The rigor of the test is in line with marketing requirements, which state that PV technology must provide a 25 to 30 year warranty for traditional crystalline silicon modules. To pass the test, the solar cell must retain 95% of its initial performance.

Their research, led by first author Randi Azmi, a postdoctoral researcher at Prof. Stefaan De Wolf’s KAUST photovoltaic lab, had to overcome a perennial vulnerability in trapped PSCs to prevent packaging leaks.

Perovskites, which are implemented through a thin-film surface coating, are sensitive to moisture and are strongly affected by it. This vulnerability of 3D perovskite films allows unnecessary infiltration of atmospheric substances, such as moisture, despite their limited heat resistance. Stability is essential to their functioning.

KAUST researchers found that the engineering and insertion of 2D-perovskite passivation layers locks in moisture while improving the energy conversion efficiency and lifetime of PSCs.

Can perovskites replace silicon?

The thin film technology of perovskites sets them apart. As with traditional solar cells, two contacts made of specific materials are always required. One collects electrons, while the other collects positively charged “holes”, which represent the exclusion of electrons.

Perovskite ink, unlike silicon wafers, can be applied instantly to a glass substrate, preceded by anti-solvent extraction and thermal annealing to fully crystallize the perovskite film. Perovskite ink is mainly made by combining salts in a polar aprotic solvent at low temperature (usually below 100°C).

One of the main advantages is that the precursor materials can be produced without the need for expensive facilities or power-intensive environments in excess of 1000°C, as is often the case with more conventional semiconductors such as silicon. .

This is a very simple way to make solar cells. Although the optoelectronic properties are not unique, they are excellent. They are on par with very high quality traditional semiconductors. It’s quite remarkable.

Stefaan De Wolf, Professor, Photovoltaic Laboratory, King Abdullah University of Science and Technology

He claims that by changing the composition, he can tune the spectral sensitivity across the spectrum of sunlight, from UV to infrared. “This is quite attractive for some applicationsadded De Wolf.

After efficiency and robustness, the last task is scaling. The majority of solar cell applications are concentrated in the utility sectors and roof panels. Although the latter is not widely used in Saudi Arabia, utility projects in the country include large photovoltaic fields in the desert.

The market is silicon-based, and it will be silicon-based for at least the next 20 years.

Stefaan De Wolf, Professor, Photovoltaic Laboratory, King Abdullah University of Science and Technology

The KAUST Photovoltaics Lab is primarily interested in improving the efficiency of perovskite solar cells in terms of developing more efficient “tandem” solutions that combine conventional silicon and perovskite.

To that end, De Wolf believes the current findings will significantly improve the credibility of perovskite-silicon tandem solar cells.

Journal reference:

Azmi, R. et al. (2022) Damp heat stable perovskite solar cells with dimensionally matched 2D/3D heterojunctions. Science.



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