Technical / research - Page 55

Researchers from the Imperial College of London and University College London have demonstrated the photovoltaic-boosting effect that phosphorene nanoribbons (PNRs) can bring to perovskite solar cells. When applied in tandem with a perovskite solar cell, PNR-boosted cells achieved an efficiency above 21%, which the researchers defined as "on par with traditional silicon cell output levels".

PNRs, first produced in 2019, have many theoretical use cases, including enhancing batteries, biomedical sensors, and quantum computing. The PNRs directly aided the perovskite cells' hole mobility, improving overall efficiency.

Scientists at the National Renewable Energy Laboratory (NREL) have experimentally synthesized a nitride perovskite material that previously only existed in theory and measured its properties in collaboration with researchers at the Colorado School of Mines.

The new material could theoretically be used for microelectromechanical devices such as the ones used in telecommunications and other areas. Nitride perovskites have been computationally predicted to be stable, but not many have been synthesized, and their experimental properties remain largely unknown, the researchers explained in their new article.

Researchers from Queen Mary University of London, in collaboration with an international team of scientists, developed a new process for creating FAPbI₃.

One of the challenges with making FAPbI₃ is that the high temperatures (150°C) used can cause the crystals within the material to 'stretch', making them strained, which favors the yellow phase that isn't suitable for solar cells. While previous reports have used small amounts of additional chemicals/additives to help form FAPbI₃ under these conditions, it can be very hard to control the uniformity and amounts of these additives when making solar cells at a very large scale, and the long-term impact of including them is not yet known.

Researchers from TNO at Holst Centre, Solliance and TU/e have jointly developed a thin and flexible perovskite-based scanner for fingerprints.

Low-resolution image-sensor arrays have been demonstrated in the past, but the high-resolution, high pixel-count image sensors suitable for commercial applications have not yet been truly achieved. The thin and flexible scanner in this new work is based on metal-halide perovskites (MHPs). Gerwin Gelinck, Chief Technology Officer TNO at Holst Centre, elaborates on the new study: 'Perovskites are marvelous materials! For the first time we show that these materials are also very good for light imaging and sensing applications. When combined with display-like transistors, we made a scanner that can capture high-resolution color images as well as biometric fingerprinting'.

Researchers from the Femtosecond Spectroscopy Unit, led by Professor Keshav Dani, at the Okinawa Institute of Science and Technology Graduate University (OIST) and Optoelectronics Materials and Device Spectroscopy Group, led by Dr. Sam Stranks at the University of Cambridge, have identified three different kinds of defect clusters in perovskite thin films, which likely occur during fabrication and may impede efficiency of perovskite solar cells.

The perovskite material lies at the heart of the solar cell, which consists of many different layers. When the sun hits the solar cell, its energy is absorbed by the perovskite, causing electrons to jump into a higher energy level and leaving holes behind. All the electrons then move in one direction through the layers of the solar cell to the electrical contact and the holes, in the other direction, thus generating a current.

Researchers from Kyung Hee University and Ulsan National Institute of Science and Technology (UNIST) in Korea have used cholesteric reflective screens, which were influenced by the skin of a beetle, to produce efficient and opaque perovskite solar cells. Unlike metal and oxide-based reflection screens, cholesteric reflective filters (ChRFs) are entirely composed of organic compounds and are much easier to design and implement.

For use in colored perovskite solar cells (PSCs), two distinct kinds of ChRFs were produced, each with a distinct cross-linking pattern (monolayer or bilayer). Since the color of the ChRFs varies depending on the angle of view, they can be utilized to make colored PSCs. As the reflective screens were created using only organic components and wet procedures, they can be used to build large and adaptable PSCs without the need for expensive suction methods.

A research team led by Erkan Aydin and Stefaan De Wolf from the KAUST Solar Center, along with co-authors from Turkey, the Netherlands and Spain, has presented an overview on the process of stopping damage from occurring to devices during the creation of transparent electrodes, particularly for a technique known as sputtering.

Damage from adding electrical contacts to sensitive semiconductors, including perovskites, can be mitigated using a buffer layer and optimized deposition. The new review gives a comprehensive overview for the origin and mitigation strategies for this technological problem.

An international research team from TU Dortmund University, the Russian Academy of Sciences and ETH Zurich has discovered that the electron dynamics in perovskite crystals are largely determined by lead. This discovery suggests that replacing this element could enable better control of the crystals' material properties.

TU Dortmund University Professor Dmitri Yakovlev's group investigated ultrafast interaction processes between optically excited charge carriers and their surroundings in perovskite crystals. The team was able to show that the magnetic properties can be regulated on an ultrafast time scale through the use of optical pulses with a duration of trillionths of a second. This proof that they can be controlled is of particular interest for possible new applications.

In a joint collaborative effort between the University of Pavia in Italy and the Technische Universität Dresden in Germany, researchers have developed a novel method to significantly improve the efficiency of inverted architecture perovskite solar cells.

The method is based on a modification of the interfaces of the perovskite active layer by introducing small amounts of organic halide salts at both the bottom and the top of the perovskite layer. Such organic halide salts, typically used for the formation of two-dimensional perovskites, led to the suppression of microstructural flaws and passivation of the defects of the perovskite layer. Using this approach, the team has achieved a power conversion efficiency of 23.7%, which they say is the highest reported to date for an inverted architecture perovskite solar cell.

Researchers at Nankai University in China have developed a Dion-Jacobson (DJ) two-dimensional perovskite solar cell. They claim it exhibits a power conversion efficiency of 18.82%, as well as remarkable light, thermal, environmental, and operational stability.

Two-dimensional (2D) Dion-Jacobson (DJ) phase perovskites have sparked interest in the scientific community due to their stability against harsh environmental conditions and their competitive performance in optoelectronic applications. Solar cells based on DJ perovskites, however, tend to show comparatively poor performance compared to their 3D counterparts.