Perovskite Solar

An international group of researchers from Swansea University, Indian Institute of Technology, University of Jammu, CSIR and Khalifa University of Science and Technology recently examined how down-conversion (DC) materials could be used to improve the performance of solar cells based on perovskite materials. The team reported that such materials could result in an electric yield enlargement by converting ultraviolet (UV) light to visible, while also providing UV shielding.

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“The DC materials can absorb the high-energy photon (300–500 nm) and re-emit a longer-wavelength photon to which the photovoltaic (PV) device is more sensitive,” the team said. “Various types of DC materials have been investigated for this purpose like quantum dots (QDs), oxides, luminescent glasses, lanthanides, and organic dyes.”

An international research group, including teams from CHOSE at the University of Rome Tor Vergata, Hellenic Mediterranean University in Greece and others, has developed a large-area perovskite solar panel with graphene-doped electron transporting layers (ETLs) and functionalized molybdenum disulfide (fMoS₂) buffer layers inserted between the perovskite layer and the hole transporting layer (HTL).

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The team reported that with increasing temperatures, the module exhibited a smaller drop in open-circuit voltage than commercially available crystalline silicon panels.

University of Cambridge scientists have created two automatically generated databases presenting photovoltaic properties and device material data for dye-sensitized solar cells (DSCs) and perovskite solar cells (PSCs).

The scientists used the ChemDataExtractor text-mining toolkit, which they described as a “chemistry-aware” natural-language-processing (NLP) tool. It was applied to 25,720 scientific articles comprising 660,881 data entries representing 57,678 photovoltaic devices. The database for the dye-sensitized devices included 475,045 entries organized into 41,680 records. The one for perovskite cells included 185,836 entries organized into 15,818 records.

The CEA at INES has reported the design of flexible perovskite solar modules with a surface area of 11.6 cm² and a power conversion efficiency of 18.9% (stabilized efficiency > 18.5%). This performance is said to be a world record for flexible perovskite modules over 10 cm².

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Perovskite-based modules before and after flexible encapsulation. Image credit: CEA

For some applications, the use of flexible substrates may be attractive for single-junction perovskite technology as it opens the way to high-speed, low-temperature printing processes. Thus, it becomes possible to use low cost substrates whereas inorganic flexible technologies, such as CIGS, require higher temperature processes and substrates that are more expensive. Many teams around the world are trying to meet the challenges of making larger area devices with sufficient stability for real-life applications. This is one of the tasks standing before partners of the European APOLO project, as part of which these results were obtained.

China-based equipment maker, SC SOLAR, has launched new cluster-type evaporation equipment specially suited for perovskite solar cells.

SC SOLAR has been working towards establishing an intelligent equipment manufacturing center, located in Suzhou. It is meant for assembling high-end photovoltaic module production lines and also for establishing an R&D center for heterojunction and perovskite tandem cells development. 

Researchers from Wuhan University and Shenzhen University in China have designed a four-junction tandem (4T) solar cell based on perovskite and copper, indium, gallium and selenium (CIGS), through a novel surface passivation technique that uses guanidine bromide (GABr).

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The team tested GABr in mixed solvents combining isopropyl alcohol (IPA) and toluene (TL), which they said can efficiently passivate interface and grain boundary defects by minimizing the IPA solubility of the perovskite surface. They compared the mixing of IPA with ethyl acetate (EA), chlorobenzene (CB), and toluene (TL) to dissolve GABr, and further optimized the concentration of GABr and the mixing ratio of the two solvents.

Researchers from Princeton University in the U.S and Sweden's Linköping University have reported the development of "the first perovskite solar cell with a commercially viable lifetime". The team estimates their device can perform above industry standards for around 30 years, far more than the 20 years used as a threshold for viability for solar cells.

Not only is the device said to be highly durable, but it also meets common efficiency standards. It is the first of its kind to rival the performance of silicon-based cells, which have been market leaders for decades. 

Researchers taking part in the EU project PERCISTAND, among them ones from the Karlsruhe Institute of Technology (KIT) and TNO, have developed perovskite/CIS tandem solar cells with an efficiency of almost 25% – the highest for this technology to date.

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In addition, this combination of materials reportedly ensures lightness and versatility, so that the use of these tandem solar cells on vehicles, portable devices and foldable or rollable devices is also conceivable. 

Scientists at the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL), CU-Boulder and the University of Toledo have demonstrated a tin-lead perovskite cell that overcomes problems with stability and improves efficiency. The new cell, a tandem design with two layers of perovskites, reached 25.5% efficiency.

The new cell also retained 80% of its maximum efficiency after 1,500 hours of continuous operation, or more than 62 days.

Researchers at Florida State University (FSU), in collaboration with ones from Argonne National Laboratory, have examined what happens when a halide perovskite faces real-world conditions, as opposed to pristine conditions of a chemistry lab.

They found that stressing halide perovskites with light and electric fields can create changes in the basic properties of the material and distort the lattice structure that is crucial to keeping this material stable.