Perovskite materials - Page 5

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. 

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. 

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.

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.

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.

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.

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.

American Perovskites (AP), a material and equipment supply company, has recently been named a finalist in the American-Made Startup Contest and awarded $200,000 to synthesize a novel family of polymer hole transport materials. AP is working with a host of players including Colorado School of Mines, TDA Research, TandemPV, and The University of Toledo. Their innovation is industrial synthesis of a novel family of polymer hole transport materials with excellent reliability, optical properties, and cost.

Another finalist in this contest was Perotech Energy, whose innovation is developing perovskite bifacial modules using high throughput and low-cost solution process with high stability and energy yield. 

Researchers from North Carolina State University, University of North Carolina at Chapel Hill, Massachusetts Institute of Technology (MIT),  National Renewable Energy Laboratory, Duke University, Wayne State University and The Hong Kong University of Science and Technology have created a mixed magnon state in an organic hybrid perovskite material by utilizing the Dzyaloshinskii-Moriya-Interaction (DMI). 

The resulting material has potential for processing and storing quantum computing information. The work also expands the number of potential materials that can be used to create hybrid magnonic systems.

Researchers from the Chinese Academy of Science (CAS) have examined the space-resolved photoluminescence and lasing behaviors of single crystal (SC) and polycrystalline (PC) perovskites upon femtosecond laser ablation. 

They discovered that femtosecond laser ablation had a considerable influence on the space-resolved photoluminescence (PL) and lasing behavior of both single crystal and polycrystalline MAPbBr₃ perovskites. Due to their distinct defect chemistries and morphologic profiles, the femtosecond laser-generated regions of the material were discovered to have different light emitting behaviors in comparison to the unaffected surface area.