Perovskites may help improve detectors for nuclear security

Researchers from the University of Florida and Pacific Northwest National Laboratory set out to improve global nuclear security by enhancing radiation detectors, and discovered, after evaluating a diverse list of over 60 candidates for alternative semiconductor compounds, that a hybrid organic-inorganic perovskite has the highest potential to succeed.

Perovskite sensors can improve equipment used for detecting and identifying radioactive materials imageBetter sensors can improve equipment used for detecting and identifying radioactive materials. (Image credit: Pacific Northwest National Laboratory)

The scientists reported that the identification of better sensor materials and the development of smarter algorithms to process detector signals are essential to enhance radiation detectors. Paul Johns, Physicist, University of Florida, said: "The end users of radiation detectors don’t necessarily have a background in physics that allows them to make decisions based on the signals that come in. The algorithms used to energy-stabilize and identify radioactive isotopes from a gamma ray spectrum are therefore key to making detectors useful and reliable".

Kyushu researchers use perovskites to create micrometer-thick OLEDs

Scientists at Kyushu University in Japan have created micrometer-thick organic light-emitting diodes (OLEDs) by integrating thick layers of hybrid perovskite with thin organic layers. Such devices have the potential to enhance the viewing angles and affordability of high-performance TVs and various other displays.

A test organic light-emitting diode (OLED) incorporating thick layers of hybrid perovskite emits green light imageA test organic light-emitting diode (OLED) incorporating thick layers of hybrid perovskite emits green light. (Image credit: William J. Potscavage Jr., Kyushu University)

OLEDs use layers of organic molecules to efficiently change electricity into light. While these molecules are excellent emitters, they are usually poor conductors of electricity. This is why researchers strive to use extremely thin layers (around 100 nm) to allow electricity to easily reach where emission takes place in the center of the devices.

Japanese team boosts the efficiency of perovskite LEDs

Researchers at the Tokyo Institute of Technology and Nihon University in Japan have explored a new approach using an exciton confinement effect to optimize highly efficient perovskite LEDs.

Japanese team improves perovksite LEDs imageThe structure of a large perovskite LED, where a layer of zinc oxide was deposited on the a-zinc silicate electron transport layer, providing greater brightness with better power efficiency. Credit: Tokyo Institute of Technology

To achieve an efficient electroluminescent device, the team required a high photoluminescence quantum yield emission layer, efficient electron hole injection and transport layers, and high light out-coupling efficiency. With each new advance in emission layer materials, new functional materials are required to realize a more efficient LED. To accomplish this goal, the authors of the study explored the performance of an amorphous zinc-silica-oxide system layered with perovskite crystals to improve the diode performance.

Research team advanced toward nontoxic perovskite solar cells

A team of scientists at Washington University in St. Louis has found what may be a more stable, less toxic semiconductor for solar applications using a novel double perovskite oxide, discovered through data analytics and quantum-mechanical calculations.

An atomic model of KBaTeBiO6 (left), scanning transmission electron micrograph showing the atomic structure of KBaTeBiO6, along with snapshot of the synthesized powder (right). Credit: WUSTLAn atomic model of KBaTeBiO6 (left), scanning transmission electron micrograph showing the atomic structure of KBaTeBiO6, along with snapshot of the synthesized powder (right). Credit: WUSTL

Rohan Mishra, assistant professor of mechanical engineering & materials science in the McKelvey School of Engineering, led an interdisciplinary, international team that discovered the new semiconductor, made up of potassium, barium, tellurium, bismuth and oxygen (KBaTeBiO6). The lead-free double perovskite oxide was one of an initial 30,000 potential bismuth-based oxides. Of those 30,000, only about 25 were known compounds.

New approach to stabilize pervoskites may push PSCs forward

Researchers at KU Leuven have explained how a promising type of perovskites can be stabilized. The team has developed a process in which the crystals turn black, enabling them to absorb sunlight. This is said to be necessary in order to use them in solar panels.

"Silicon forms a very strong, rigid crystal. If you press on it, it won't change its shape. On the other hand, perovskites are much softer and more malleable," explains Dr. Julian Steele of the KU Leuven Centre for Membrane Separations, Adsorption, Catalysis, and Spectroscopy for Sustainable Solutions (cMACS). "We can stabilize them under various lab conditions, but at room temperature, the black perovskite atoms really want to reshuffle, change structure, and ultimately turn the crystal yellow".