Perovskite Solar - Page 62

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).

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.

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.

Researchers from The Australian National University, Flinders University, University of New South Wales and The University of Sydney have developed a perovskite solar cell with a novel passivation process based on the use of guanidinium (Gua) and octylammonium (Oa) spacer cations.

 A schematic showing the device structure and the surface incorporation of GuaBr, OABr, and their mixture. Image from RL Solar

The team claims that guanidinium salts can improve the performance of the perovskite film, as guanidinium ions are capable of penetrating into the bulk of the perovskite material and localizing at the grain boundaries (GBs).

The U.S. Department of Energy (DoE) has selected 19 projects for which to grant a total funding of $6 million, to pursue innovative, targeted, early-stage ideas in solar energy research and development. The projects were selected through the Solar Energy Technologies Office (SETO) Small Innovative Projects in Solar (SIPS) 2022 Funding Program.

Projects were awarded in two solar energy research areas: PV and concentrating solar-thermal power (see CSP winners here). PV projects will improve power conversion efficiency, energy output, reuse and recycling processes, service lifetime, and manufacturability of PV technologies. Of the 19 selected project, 3 were perovskite-related.

Recent reports claim that South Korea's Hyundai auto group has teamed up with a research team at Ulsan National Institute of Science and Technology (UNIST) to develop new perovskite solar cells that can charge vehicles while they are under the sun. 

Hyundai Motor already released solar roofs with silicon solar panels, but their acceptance has been slow without improvements in weight and efficiency, as silicon solar cells are quite heavy and have technical limitations in improving efficiency. In a recent ceremony, the Ulsan National Institute of Science and Technology (UNIST) opened a joint laboratory with Hyundai to develop high-efficiency, large-area perovskite-silicon tandem cells and apply them to solar roofs. The joint laboratory will operate for three years until May 2025.

Australian researchers from Monash University and CSIRO have reported a way to improve the energy efficiency and longevity of solar integrated glass, while also allowing more natural light to pass through it. The researchers have demonstrated power conversion efficiencies of 15.5% and 4.1% for different types of prototype semi-transparent solar cells, with visible transmittance of 20.7% and 52.4% respectively.

This work builds on achievements made two years ago, when the same team created a solar window prototype that let through 10% of visible light and achieved 17% power conversion efficiency. According to the team, the upper power conversion efficiency achieved in the newer prototype is slightly lower than was achieved back in 2020 – 15.5% compared to 17% – but the pass-through of visible light is “significantly greater”, increasing their viability for real-world applications.

Researchers from the City University of Hong Kong and the Southern University of Science and Technology in Shenzhen, China, have shown that a self-assembled monolayer can facilitate the formation of a large-area perovskite film using a blade-coating process, thus promote the upscaling of perovskite photovoltaic technology.

Researchers build perovskite solar cells with layers of material deposited on an underlying substrate. In adapting the high-speed blade-coating method for perovskite thin-film deposition, the researchers realized that the surface properties of the substrate are critical for large-area coating and perovskite growth. The current process leaves voids at the buried interface of the perovskite film that is detrimental to the device performance. “To solve this problem, we have screened various hole-transporting materials and found that self-assembled monolayers are a class of promising materials for the upscaling of perovskite devices,” said Alex Jen, a professor at City University of Hong Kong.