Efficiency - Page 40

Researchers from The Hebrew University of Jerusalem and Ben-Gurion University of the Negev in Israel, have studied the two-step deposition of perovskites in mesoporous-carbon-based perovskite solar cells. The team studied the effect of the different deposition parameters on the PV performance and stability.

b) Schematic illustration of the two-step deposition process. The first stage includes dropping of the PbI2 þ PbBr2 solution, the second step includes dipping into the cation solution of FAI þ MABr. Image from article

The influence of the dipping time on the photovoltaic parameters was investigated using charge extraction and intensity-modulated photovoltage spectroscopy (IMVS) measurements. By modifying the perovskite precursors' concentration and the dipping time, a PCE of 15% was achieved. The dipping time in the perovskite deposition of this solar cell structure is critical due to its thickness and mesoporous structure.

An international research team has developed a flexible quantum dot solar cell based on all-inorganic cesium-lead iodide (CsPbI₃) perovskite.

The researchers built the cell by integrating quantum dots (QDs) with high surface areas into a thin hybrid interfacial architecture (HIA) and by adding phenyl-C61-butyric acid methyl ester (PCBM), which is known as one of the best-performing electron acceptors commonly used in organic photovoltaic devices, into the CsPbI₃ quantum dot layer.

United Renewable Energy (URE), a U.S -based solar company, has announced that it has made a breakthrough in developing perovskite solar cells in collaboration with National Taiwan University, with energy conversion rates reaching as high as 26%, the company claims. It seems that these cells by URE are silicon/perovskite tandems.

URE said it has also developed N-type HJT and TOPCon solar cells. URE has reportedly begun shipments for HJT solar cells with a maximum energy conversion rate of 24.5% and will start small-volume production of TOPCon solar cells later in 2021.

A research team, led by Dr. Luigi Angelo Castriotta at the at University of Rome Tor Vergata's CHOSE Center for Hybrid and Organic Solar Energy, has reported impressive results on methylammonium free perovskites processed in air, using a scalable technique based on infrared annealing and potassium doped graphene oxide as an interlayer.

The team reached efficiencies of 18.3% and 16.10% on 0.1cm² cell and on 16cm² module respectively, with enhanced stability compares to the standard multi cation reference.

Scientists from the University of North Carolina have developed a perovskite solar cell with an efficiency of 23.2% by adding benzylhydrazine hydrochloride (BHC) as an iodine (I) reductant agent in precursor solutions such as methylammonium iodide (MAI) and formamidinium iodide (FAI).

'Preventing the degradation of perovskite precursor solutions is equally important compared to post-fabrication device encapsulation, because large-area perovskite modules are generally manufactured in air and perovskite precursor inks are generally prepared in large quantity and stored for days or months,' the scientists said.

A team of researchers at the French National Solar Energy Institute (INES) at the country's Alternative Energies and Atomic Energy Commission (CEA) has announced achieving 18% power conversion efficiency of perovskite solar modules.

They were able to achieve this level on an active surface area of 10 cm² under illumination of 1 STC sun, using a coating step carried out in air followed by a gas quenching conversion step to form the desired perovskite material. This material was developed without methyl ammonium comprising multi-cations and a mix of halogens.

A team of researchers at MIT (along with colleagues from South Korea and Georgia) has developed a new approach to the design of perovskite cells by adding a specially treated conductive layer of tin dioxide bonded to the perovskite material, which provides an improved path for the charge carriers in the cell. By also modifying the perovskite formula, the researchers have reportedly boosted its overall efficiency as a solar cell to an impressive 25.2%.

On top of many other attractive properties, perovskites have a higher bandgap than silicon, which means they absorb a different part of the light spectrum and thus can complement silicon cells to provide even greater combined efficiencies. But even using only perovskite, MIT's Jason Yoo says, 'what we're demonstrating is that even with a single active layer, we can make efficiencies that threaten silicon, and hopefully within punching distance of gallium arsenide. And both of those technologies have been around for much longer than perovskites have.'

Solliance and U.S-based MiaSolé announced a new record - power conversion efficiency of 26.5% on a tandem solar cell that combined a top rigid semi-transparent perovskite solar cell with a bottom flexible copper indium gallium selenide (CIGS) cell.

This impressive efficiency was achieved by optimizing the bandgap and the efficiency of both the rigid semi-transparent perovskite top cell and the flexible CIGS bottom cell. The CIGS was roll to roll produced on steel foil, with a power conversion efficiency of 20.0%.

Researchers from the Shaanxi Normal University in China have designed a perovskite solar cell based on methylammonium lead iodide (MAPbI₃) through a dual passivation technique that simultaneously passivates trap defects in both the perovskite and electron transport layer (ETL) films.

'So far, most techniques for modifying perovskite solar cells focus on either the perovskite or electron transport layer,' the research group reported, noting that the ETL must have decent optical transmittance and high electron mobility to extract photo'induced carriers and contribute to the solar cell efficiency.

A research team from the Okinawa Institute of Technology (OIST) in Japan has developed a mini perovskite solar module based on large'area uniform and dense perovskite films with a thickness of more than one'micrometer.

The scientists fabricated two modules, sized 5x5cm² and 10x10cm², with efficiencies of 14.55% and 10.25%, respectively, which reportedly rely on perovskite layers with high crystallinity, large grain sizes, and small surface roughness.