Researchers deepen understanding of glass formation and crystallization kinetics in 2D metal halide perovskites

Researchers from Duke University and North Carolina State University have reported glass formation for low-melting-temperature 1-MeHa2PbI4 (1-MeHa = 1-methyl-hexylammonium) using ultrafast calorimetry, thereby extending the range of metal halide perovskite (MHP) glass formation across a broader range of organic (fused ring to branched aliphatic) and halide (bromide to iodide) compositions. 

A few years ago, Akash Singh and collaborators at Duke University set out to explore the realm of glassy perovskites, a departure from the traditionally studied crystalline perovskites. Since then, this topic sparked interest, resulting in the establishment of a novel research domain centered around glass-forming hybrid perovskite semiconductors with reversible switching. This recent discovery of glass formation in MHPs opens new opportunities associated with reversible glass-crystalline switching, with each state offering distinct optoelectronic properties. However, the previously reported [S-(−)-1-(1-naphthyl)ethylammonium]2PbBr4 perovskite is a strong glass former with sluggish glass-crystal transformation time scales, pointing to a need for glassy MHPs with a broader range of compositions and crystallization kinetics.   

Read the full story Posted: Aug 16,2023

Researchers explore the fatigue behavior of 2D hybrid organic–inorganic perovskites

Researchers from Texas A&M University, Northwestern University, University of South Florida and University of Illinois Urbana-Champaign have studied the fatigue behavior of 2D hybrid organic-inorganic perovskites (HOIPs) in practical applications.

The application of repeated or fluctuating stresses below the material's strength, known as fatigue loading, often leads to failure in 2D hybrid materials. However, the fatigue properties of HOIP materials have remained elusive despite their widespread use in various applications. The research group demonstrated how fatigue loading conditions, wearing different components, would affect the lifetime and failure behavior of the materials. Their results provide insights into designing and engineering 2D HOIPs and other hybrid organic-inorganic materials for long-term mechanical durability.

Read the full story Posted: Jul 29,2023

Researchers develop novel materials acceleration platform to identify perovskite materials with desirable properties for PSCs

Researchers from North Carolina State University, National Synchrotron Light Source II at Brookhaven National Laboratory and Rey Juan Carlos University have created a novel materials acceleration platform (MAP), essentially a robot capable of conducting experiments more efficiently and sustainably to develop a range of new semiconductor materials with desirable attributes. The researchers have demonstrated that the new technology, called RoboMapper, can rapidly identify new perovskite materials with favorable properties and improved potential for creating stable and efficient solar cells.

“RoboMapper allows us to conduct materials testing more quickly, while also reducing both cost and energy overhead – making the entire process more sustainable,” says Aram Amassian, corresponding author of a paper on the work and a professor of materials science and engineering at North Carolina State University.

Read the full story Posted: Jul 26,2023

Researchers demonstrate the unique potential of perovskite nanocrystals to serve as scalable, colloidal sources of indistinguishable single photons

Researchers at MIT have prepared large CsPbBr3 nanocrystals and observed direct evidence of interference between indistinguishable single photons sequentially emitted from a single nanocrystal. 

While the work is currently a fundamental discovery of these materials' capabilities, it might ultimately pave the way to new optically based quantum computers, as well as possible quantum teleportation devices for communication, the researchers say. 

Read the full story Posted: Jun 26,2023

Researchers examine perovskite-sensitized upconversion under real-world conditions

Researchers at Florida State University, the FAMU-FSU College of Engineering, the University of Colorado Boulder and Argonne National Laboratory have studied the effects of two stressors, heat and light, on the triplet generation process at the perovskite/rubrene interface. Following exposure to both stressors, local discrepancies across the upconversion device were discovered. This work emphasizes the challenges and continued potential for the integration of perovskite-sensitized upconversion (UC) into commercial photovoltaic devices. 

The first region showed changes to the morphology, and no detectable upconverted emission was observed. Through the combination of optical microscopy and spectroscopy, crystallization of the organic semiconductor layer, degradation of dibenzotetraphenylperiflanthene, and concurrent degradation of the perovskite sensitizer were found. These effects culminate in a reduction in both triplet generation and triplet–triplet annihilation. In the second region, no changes to the morphology were present and visible UC emission was observed following exposure to both stressors. To probe the triplet sensitization process at elevated temperatures, transient absorption spectroscopy was performed. The presence of the excited spin-triplet state of rubrene at 60 °C highlighted successful triplet generation even at elevated temperatures. 

Read the full story Posted: Jun 24,2023

Researchers search for materials to improve SnO2 ETLs for better perovskite devices

Researchers from the Chinese Academy of Sciences (CAS) have used graphdiyne oxide (GDYO), fluorinated GDYO (FGDYO) and nitrogen-doped GDYO (NGDYO) to improve the SnO2 electron transport layer (ETL) in perovskite solar cells and revealed the relevant mechanism using synchrotron radiation technology. 

The team tracked the growth process of SnO2, PbI2 and perovskite using in situ XRD and the chemical bonds on the interface between ETL and the active layer using in situ XAFS. They found that the stronger interaction between the doped SnO2 and PbI2 inhibited PbI2 crystallization in perovskite layers and gave more opportunity for the PbI2 precursor to form perovskite, thus making perovskite crystallize better.

Read the full story Posted: Jun 14,2023

Researchers use supercomputer to better understand how to assemble cubic perovskites with spherical nanoparticles

Researchers from Ames National Laboratory worked with scientists at the Swiss Federal Institute of Technology in Zürich (ETH Zurich) to understand how to assemble perovskites (that are shaped as nanocubes) with other sphere-shaped nanocrystals. 

The scientists used the Expanse supercomputer at the San Diego Supercomputer Center (SDSC) at UC San Diego to identity the general rules that enable the assembly of nanocubes like perovskites with spherical nanoparticles. Ultimately, they conducted a study to assist with the design of future nanoparticle-based materials. Their recent paper provides details on both their results and problems when pairing the perovskites with spherical nanocrystals.

Read the full story Posted: Jun 10,2023

Researchers demonstrate laser-driven control of fundamental motions of the lead halide perovskite atomic lattice

An international team of scientists from Fritz Haber Institute of the Max Planck Society, École Polytechnique in Paris, Columbia University in New York, and the Free University in Berlin have demonstrated laser-driven control of fundamental motions of the lead halide perovskite (LHP) atomic lattice.

Sketch of the experimental pump-probe configuration. Image from Science Advances

By applying a sudden electric field spike faster than a trillionth of a second (picosecond) in the form of a single light cycle of far-infrared Terahertz radiation, the team unveiled the ultrafast lattice response, which might contribute to a dynamic protection mechanism for electric charges. This precise control over the atomic twist motions could allow to create novel non-equilibrium material properties, potentially providing hints for designing the solar cell material of the future.

Read the full story Posted: Jun 06,2023

NASA claims perovskite solar cells tested in space degrade less than devices tested on Earth

US space agency NASA has revealed the results of an experiment it conducted to assess the performance and durability of perovskite solar cells on the International Space Station. The surprising discovery was that perovskite solar cells tested in space exhibit less degradation than reference devices tested on Earth. The specific factors in the space environment that contributed to the superior performance of the perovskite absorber film currently remain unknown.

NASA tested a perovskite absorber over a 10-month period in order to assess its resistance to vacuum, extreme temperatures, radiation, and light stressors simultaneously.

Read the full story Posted: May 25,2023

Researchers achieve solar-driven liquid multi-carbon fuel production using a standalone perovskite–BiVO4 artificial leaf

University of Cambridge researchers have used perovskites to develop a solar-powered technology that converts carbon dioxide and water into liquid fuels that can be added directly to a car’s engine as drop-in fuel.  

The researchers relied on photosynthesis to convert CO2, water and sunlight into multicarbon fuels – ethanol and propanol – in a single step. These fuels have a high energy density and can be easily stored or transported.

Read the full story Posted: May 22,2023