Phys.org March 18, 2024 Freestanding oxide membranes have a variety of interesting applications, but pulling these materials off the substrate after synthesis can be challenging. An international team of researchers (China, Austria) has developed a water-soluble sacrificial layer, “super-tetragonal” Sr4Al2O7 (SAOT). The low-symmetric crystal structure enabled a superior capability to sustain epitaxial strain, allowing for broad tunability in lattice constants resulting in structural coherency and defect-free interface in perovskite ABO3/SAOT heterostructures effectively restraining crack formation during the water release of freestanding oxide membranes. For a variety of nonferroelectric oxide membranes, the crack-free areas can span up to a millimeter in […]
Tag Archives: Perovskites
Single proton illuminates perovskite nanocrystals-based transmissive thin scintillators
Science Daily February 1, 2024 Current particle detectors use bulk crystals, and thin-film organic scintillators have low light yields and limited radiation tolerance. An international team of researchers (Singapore, China) has developed transmissive thin scintillators made from CsPbBr3 nanocrystals, designed for real-time single proton counting. The scintillators exhibited exceptional sensitivity, with a high light yield when subjected to proton beams. The enhanced sensitivity was attributed to radiative emission from biexcitons generated through proton-induced upconversion and impact ionization. The scintillators could detect as few as seven protons per second, a sensitivity level far below the rates encountered in clinical settings. According […]
Nanoscale rust: The future of magnets?
Phys.org October 5, 2023 Multiferroics have tremendous potential to revolutionize logic and memory devices through new functionalities and energy efficiencies. To better understand and enhance their ferroic orders and couplings an international team of researchers (Canada, USA – Lawrence Berkeley National Laboratory, Argonne National Laboratory) used epsilon iron oxide (ϵ-Fe2O3) as a model system with a simplifying single magnetic ion. Using 15, 20, and 30 nm nanoparticles, they found that a modified and size-dependent Fe–O hybridization changed the spin–orbit coupling. However, the size effects disappeared in the high-temperature phase where the strongest Fe–O hybridization occurred. By manipulating hybridization, they could […]
Striking rare gold: Researchers unveil new material infused with gold in an exotic chemical state
Phys.org September 30, 2023 Although Cu2+ is ubiquitous, the relativistic destabilization of the 5d orbitals makes the isoelectronic Au2+ exceedingly rare, typically stabilized only through Au–Au bonding or by using redox non-innocent ligands. An international team of researchers (USA – Stanford University, UC Berkeley, SLAC National Accelerator Laboratory, Lawrence Berkeley National Laboratory, Canada) have developed the perovskite Cs4AuIIAuIII2Cl12, an extended solid with mononuclear Au2+ sites, which is stable to ambient conditions and characterized by single-crystal X-ray diffraction. The 2+ oxidation state of Au was assigned using 197Au Mössbauer spectroscopy, electron paramagnetic resonance, and magnetic susceptibility measurements, with comparison to paramagnetic […]
Better cybersecurity with new material
Science Daily September 4, 2023 Perovskite light emitting diodes (PeLEDs) has the potential to revolutionize the fields of optical communication and lighting devices, due to their simplicity of fabrication and outstanding optical properties. An international team of researchers (Sweden, Chile) has demonstrated that PeLEDs could be used in the field of quantum technologies by implementing a highly secure quantum random number generator (QRNG) which is posed to replace classical random number generators in applications such as encryption and gambling, and therefore need to be cheap, fast and have integration capabilities. Using a compact metal-halide PeLED source, the team generated random […]
Growing triple-decker hybrid crystals for lasers
Phys.org August 31, 2023 Although two-dimensional organic semiconductor-incorporated perovskites are a promising family of hybrid materials for optoelectronic applications, tuning their structures and specific properties has remained challenging. By choosing the right solvent a team of researchers in the US (Purdue University, Duke University, Lawrence Berkeley National Laboratory) has developed a general method to tune the dimensionality of phase-pure organic semiconductor-incorporated perovskite single crystals during their synthesis. They showed that the length of the conjugated semiconducting organic cations and the dimensionality of the inorganic layers could be manipulated at the same time. The energy band offsets and exciton dynamics at […]
Linking two solar technologies is a win-win for efficiency and stability
Nanowerk September 5, 2023 Although metal halide perovskites have rapidly enabled a range of high-performance photovoltaic technologies, their catastrophic failure under reverse voltage bias poses a roadblock for their commercialization. An international team of researchers (Princeton University, Saudi Arabia) conducted a series of stress tests to compare the reverse-bias stability of perovskite single-junction, silicon single-junction, and monolithic perovskite/silicon tandem solar cells. They demonstrated that the tested perovskite/silicon tandem devices were considerably more resilient against reverse bias compared with perovskite single-junction devices. The origin of such improved stability stemmed from the low reverse-bias diode current of the silicon subcell. This translated […]
Device makes hydrogen from sunlight with record efficiency
Science Daily July 20, 2023 An international team of researchers (USA – Rice University, National Renewable Energy Laboratory, Lawrence Berkeley National Laboratory, Germany, France) designed and fabricated a conductive adhesive-barrier (CAB) that translates >99% of photoelectric power to chemical reactions. The CAB enabled halide perovskite-based photoelectrochemical cells with two different architectures that exhibited record STH efficiencies. The first, a co-planar photocathode-photoanode architecture, achieved an STH efficiency of 13.4% and 16.3 h to t60, solely limited by the hygroscopic hole transport layer in the n-i-p device. The second was formed using a monolithic stacked silicon-perovskite tandem, with a peak STH efficiency of […]
New device gets scientists closer to quantum materials breakthrough
Phys.org June 17, 2022 An international team of researchers (USA – UC Berkeley, University of Nebraska, Argonne National Laboratory, Canada) has found a way to combine the advantages of light and matter at room temperature suitable for finding the global minimum of mathematical formulations at room temperature. They used solution-grown halide perovskite grown under nanoconfinement. This produced exceptional smooth single-crystalline large crystals with great optical homogeneity. Its material properties could enable future studies at room temperature rather than ultracold temperatures. They showed that XY spin lattice with many coherently coupled condensates that can be constructed as a lattice with a […]
Perovskite photovoltaics for a greener Internet-of-Things
Nanowerk April 28, 2022 An international team of researchers (UK, USA – City College of New York) reviewed the novel device concepts that comprise photovoltaic cells alone or in tandem with batteries or supercapacitors, acting as the main power supply to another microelectronic component, enabling self-powered electronics for the Internet of Things (IoT). They emphasize the specific requirements posed by such applications to pave the way to large scale commercialization. They highlighted the importance of supporting a greener IoT ecosystem by eliminating toxic materials and solvents in the device fabrication process…read more. Open Access TECHNICAL ARTICLE