An international research group, led by Dr. Yang Bin from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS), has developed cadmium (Cd)-based perovskite single crystals with long afterglow and high luminous quantum yield, and investigated its afterglow luminescence dynamics mechanism.

Afterglow materials have the ability to store multiple radiations such as visible photons, ultraviolet rays, and X-rays. They are widely used in display, biological imaging, anti-counterfeiting technology, and data storage. However, traditional all-inorganic phosphors, such as oxide, sulfide, and nitride-based afterglow materials, have high lattice energy and usually need to be produced by high-temperature processing (>1000°C), which brings considerable energy consumption and safety risks to production and preparation.

In June 2021, Tokyo Chemical Industry Company Limited (TCI) started offering new hole selective self-assembled monolayer (SAM) forming agents, 2PACz [Product Number: C3663], MeO-2PACz [D5798] and Me-4PACz [M3359] for high performance perovskite solar cells and OPVs. Now, TCI has expanded its range of SAMs by adding two new high-efficiency materials: Me-2PACz [M3477] and Br-2PACz [B6391].

The SAM materials enable efficient, versatile and stable p-i-n perovskite solar cell devices. These materials are useful for tandem solar cells as they grant conformal coverage on rough textures. In fact, a perovskite solar cell that uses the SAM hole transport layer can realize more than 20% efficiency without using dopants or additives. Perovskite-Silicon tandem solar cells that use Me-4PACz as a hole contact material realized 29.15% efficiency. Costs are lowered thanks to extremely low material consumption, and the processing is very simple and scalable.

Researchers from the Department of Energy’s Ames National Laboratory and The University of Toledo have developed a new characterization tool that allowed them to gain unique insight into a perovskite material. Led by Ames' Jigang Wang, the team developed a microscope that uses terahertz waves to collect data on material samples. The team then used their microscope to explore Methylammonium Lead Iodide (MAPbI₃) perovskite.

Richard Kim, a scientist from Ames Lab, explained the two features that make the new scanning probe microscope unique. First, the microscope uses the terahertz range of electromagnetic frequencies to collect data on materials. This range is far below the visible light spectrum, falling between the infrared and microwave frequencies. Secondly, the terahertz light is shined through a sharp metallic tip that enhances the microscope’s capabilities toward nanometer length scales.

Researchers from Israel's Bar-Ilan University and Weizmann Inst. of Science have measured the effect of humidity on hardness and elastic modulus (E) for two series of lead halide perovskite single crystals. The results indicated the influence of hydrogen (H)-bonding, bond length, and polarization of the ions in lead halide perovskite single crystals.

The team detected an inverse relation between hardness and modulus, which was strengthened with increased humidity. Their findings shed light on the material's distinct structure and properties at the atomic scale. The conclusion of this work was based on the evaluation of outcomes of various nano-indentation techniques that differentiated between surface and bulk E and explored different manifestations of hardness.

Researchers from Rice University, Northwestern University, Purdue University, University of Washington, CNRS and Argonne National Laboratory have addressed a long-standing issue in making stable, efficient solar panels out of halide perovskites. It took finding the right solvent design to apply a 2D top layer of desired composition and thickness without destroying the 3D bottom one (or vice versa). Such a cell would turn more sunlight into electricity than either layer on its own, with better stability.

The team, led by Chemical and biomolecular engineer Aditya Mohite and his lab at Rice’s George R. Brown School of Engineering, recently reported their success at building thin 3D/2D solar cells that deliver a power conversion efficiency of 24.5%.

Scientists at the U.S. Department of Energy's (DOE) Argonne National Laboratory and Purdue University have developed a machine learning method for screening many thousands of compounds as solar absorbers. Argonne's Maria Chan and Purdue's Arun Mannodi-Kanakkithodi, who led the study, chose to work with a form of artificial intelligence (AI) that uses a combination of large data sets and algorithms to imitate the way that humans learn. It learns from training with sample data and past experience to make ever better predictions.

The team used their machine learning method to assess the solar energy properties of halide perovskites. "Unlike silicon or cadmium telluride, the possible variations of halides combined with perovskites are essentially unlimited," said Chan. "There is thus an urgent need to develop a method that can narrow the promising candidates to a manageable number. To that end, machine learning is a perfect tool."

Researchers from the University of Melbourne, Monash University and IEK-5 Photovoltaik in Germany have developed a large-area laser beam induced current microscope that has been adapted to perform intensity modulated photocurrent spectroscopy (IMPS) in an imaging mode. The new imaging tool could reportedly spot previously undetectable defects in solar cells.

The team's IMPS microscopy was used to study the spatial dependence of moisture-related degradation in a back-contact PSC. Using diffusion-recombination theory, the researchers modeled the IMPS response from which ambipolar diffusion length maps can be extracted from low-frequency experimental data. Apart from this important metric, they illustrated how other frequency bands can be used to study the degradation of a PSC.

Researchers have reported a prototype device that could someday replace existing air-conditioners. The device is more environmentally friendly and uses perovskite-based solid refrigerants to efficiently cool a space.

Currently used hydrofluorocarbon refrigerants used in air conditioners and other cooling devices are potent greenhouse gases and major drivers of climate change. This new work has the potential to tackle this issue and offer a greener solution.

Researchers from Ulsan National Institute of Science and Technology (UNIST) have reported the deposition of dense and uniform α-formamidinium lead triiodide (α-FAPbI₃) films using perovskite precursor solutions dissolved in ethanol-based solvent. This addresses the issue of halide perovskites generally not being completely soluble in most non-toxic solvents.

The research team, led by Seok Sang-il, has worked out an ethanol-based perovskite precursor solution by designing a complex compound structure so that perovskites can be dissolved well in ethanol. In their study, the researchers obtained power conversion efficiencies of 24.3% using a TiO₂ electrode, and of 25.1% with a SnO₂ electrode.

University of Cambridge scientists have developed perovskite-based floating ‘artificial leaves’ that generate clean fuels from sunlight and water. The team expects these could eventually operate on a large scale at sea. The ultra-thin flexible devices take their inspiration from photosynthesis. Since the low-cost, autonomous devices are light enough to float, they could be used to generate a sustainable alternative to gasoline without taking up space on land.

A floating artificial leaf which can generate clean fuel from sunlight and water – on the River Cam near King’s College Chapel in Cambridge, UK. Image credit: Virgil Andrei, from: Scitechdaily

Outdoor tests of the lightweight leaves on the River Cam showed that they can convert sunlight into fuels as efficiently as plant leaves. River Cam is the main river flowing through Cambridge in eastern England, and the testing occurred near iconic Cambridge sites including the Bridge of Sighs, the Wren Library, and King’s College Chapel.