Halide perovskites

2024

Full-format domestic solar panel presented at MISIS University

NUST MISIS presented the first in Russia full-format battery based on hybrid perovskites, made only from domestic materials and ready to be put into production. The solar panel is cheaper than analogues at cost, and the manufacturing cycle is 8-10 hours. It can be installed both in a private house and on industrial facilities of enterprises, for which the implementation of the "green" agenda is a priority. The connection of many subcells in the panel provides high power generation in shading and cloudy weather conditions. The development opens up new horizons for the operation of solar energy even in the Arctic and the Far North. The university announced this on October 4, 2024. Read more here.

New semiconductor for optoelectronics obtained at NRNU MEPhI

Researchers at NRNU MEPhI as part of an international scientific team synthesized strontium stannate doped with lanthanum, ruthenium and indium atoms and determined its electronic, magnetic and optical characteristics. This material can be used in optoelectronics, memory devices and spintronics. The university announced this on September 3, 2024.

The material belongs to the category of perovskite - that is, crystalline compounds, the molecule of which consists of 5 atomic-two positive ions and three negative ones. Perovskites, which include one tin atom and three oxygen atoms, are called stannates and systematically attract the attention of researchers because they have prospects for applications in the field of photocatalysis, power and sensorics.

One of the key compounds in this family is strontium stannate, whose molecule consists of one strontium atom of one tin atom and three oxygen atoms (SrSnO3). Strontium moanate is distinguished by its structural flexibility, reduced lattice parameters and a sufficiently wide band gap of the order of 4 eV. In addition, when alloying, in other words, replacing strontium or tin with atoms of other elements, the orthorhombic structure of the perovskite is SrSnO3 distorted, resulting in absorption in the visible radiation range.

Despite the fact that stannates are intensively studied, as of September 2024, there are no detailed experimental or theoretical studies showing how joint doping, for example, with indium and ruthenium atoms affects the electronic and magnetic properties of SrSnO3, in a thin film or bulk sample format.

Together with foreign colleagues, NRNU MEPhI researchers synthesized strontium stannate doped with lanthanum, ruthenium and indium atoms. Nanoscale semiconductor perovskite La0.25Sr0.75Sn0.4In0.25Ru0.35O3 (LSSIRuO, see Fig.) was obtained as a powder using environmentally friendly mechanochemical synthesis, known for its simplicity and cost-effectiveness.

Control of the resulting material by X-ray diffraction analysis and infrared spectroscopy confirmed that the sample crystallized into a GdFeO3 perovskite-type structure.

Scientists have determined the electronic, magnetic and optical characteristics of the material. For example, data from experiments and theoretical analysis indicate a rather narrow semiconductor gap ~ 1.5 eV compared to non-ligated strontium stannate.

We have found that the band gap can vary depending on the ratio of tin and ruthenium atoms in the sample. Thus, we can conclude that additional doping with ruthenium atoms stimulates the transition from a dielectric state to a semiconductor state, and then to a semi-metallic/metal one, "commented Mikhail Maslov, professor at the Institute of Nanotechnology in Electronics, Spintronics and Photonics at NRNU MEPhI.

According to him, this effect allows you to adjust the electronic characteristics of the material, adjusting the number of atoms of modifying additives.

In addition, the authors found that LSSIRuO showed higher electrical conductivity compared to unsubstituted SrSnO3, and also showed ferromagnetic nature at temperatures below 155 K.

Thus, the small width of the semiconductor slit, combined with electrical and magnetic characteristics, according to scientists, makes LSSIRuO a promising candidate for use in optoelectronics, as well as in memory and spintronics devices.

2023

Scientists have proposed technology for making X-ray detectors based on perovskite material

Scientists at the University of Science and Technology MISIS and the Center for Diagnostics and Telemedicine DZM have proposed technology for the manufacture of X-ray detectors used to check luggage at the airport or for computed tomography in hospitals. The University announced this on August 25, 2023.

Detectors based on perovskite material will reduce the cost of devices and increase sensitivity to X-ray radiation. The opening of their production in Russia will allow import substitution of foreign analogues. Read more here.

ITMO has increased the efficiency of perovskite solar panels

The physicists of ITMO, Alfer University and the Roman university Tor Vergata have developed perovskite solar cells with increased efficiency. It was possible to optimize the characteristics of solar panels using semiconductors in the form of thread-like nanocrystals. The proposed technology opens up additional opportunities in the creation of solar power plants and next-generation optical devices. The results of the study are published in the journal ACS Applied Energy Materials. This was announced on April 5, 2023 by representatives of ITMO. Read more here.

NUST MISIS scientists have developed a prototype of a perovskite solar cell

Young scientists NITU MISIS developed a prototype of a perovskite solar cell with a duration of 3500 hours, and also scaled it to a photo module. Such results were achieved by the use of chlorine alloying additives in the composition of an absorbing perovskite thin film. Already in February 2023, prototypes can be used in the form of compact power supplies for low-power electronics. According to the researchers, the prototype is ready for field tests and pilot testing. The results of the study are published in the journal Solar RRL. This was announced on February 6, 2023 by representatives of NUST MISIS. Read more here.

2021: Creating water-resistant perovskite nanocrystals to study living cells

On September 17, 2021, ITMO University announced that its scientists have created nanocrystals of perovskites that retain their optical properties in water and biological fluids for a long time. The obtained material can open up possibilities in the field of optical visualization of biological objects. This is important for studying the internal organs of living organisms and monitoring the course of diseases. The results of the study are published in the Journal of Physical Chemistry Letters.

Nanomaterials based on halide perovskites due to their properties, luminescence and low cost are actively used to create nanolasers, LEDs. They also have prospects in bioimaging: perovskite nanoparticles can be used to develop imaging systems and study biological processes inside cells and living organisms. However, the main limitation that does not yet allow them to be used as luminous markers is that when they enter aqueous environments, they lose their physical properties.

"When moisture enters perovskites, cesium salt instantly washes out of them, without which the glow becomes impossible. One way to make perovskites water-resistant is to cover them with a special shell. The task seems simple, but so far it has not been possible to effectively protect the material from water, while maintaining its full functionality, "- tells a researcher at the New Physics and Technology Department of ITMO Lev Zelenkov.

ITMO scientists took just over a year to find a way to protect perovskite nanoparticles from the penetration of water molecules and various chemicals. As a result, they managed to obtain perovskite nanocrystals coated with a special silicate shell. It is modified with organic hydrophobic (water repellent) chemical groups. Thanks to this shell, perovskites retain their properties in aqueous environments for up to one week.

"We tested the nanomaterial we created not only in water, but also in cell cultures. Tumor cells were taken as a model. We added water-resistant perovskites to them and visualized them with optical microscopy. It is important that even when perovskite interacts with the cell, perovskites did not degrade and continued to emit light, which indicated their stability, "- says Mikhail Zyuzin, senior researcher at the New Physics and Technology Institute of ITMO.

The next step will be in vivo studies, that is, in laboratory animals. Scientists will look at whether perovskite nanoparticles will be stable inside a living organism. The researchers also plan to reduce the potential toxicity of perovskites, for example, by replacing lead with a more environmentally friendly material. This will make the nanomaterial safer to use.

"By confirming the robustness of our nanomaterials in aqueous environments, we have shown only one application. But development can be useful not only in biology. Water-resistant perovskite nanocrystals can be used as a decorative luminescent dye, as well as labels to protect documents. First of all, it was important for us to create a real working solution. Now we will test it in different conditions, "- concluded professor of the New Physics Department of ITMO Sergey Makarov.

The study is supported by a grant from the RPF and the Ministry of Science and Higher Education.

2020

Presentation of coating technology for augmented reality screens using halide perovskite film

On November 9, 2020, ITMO announced the development of a coating with which ordinary glass can be turned into a "smart" surface. It is assumed that the technology will be in demand to create augmented reality screens that provide users with additional information about what is happening around. Also, the coatings will allow converting solar energy into electricity. Read more here.

Development of an ultra-precise method for laser treatment of halide perovskites

Scientists from the Far Eastern Federal University (FEFU) and ITMO University, together with colleagues from Germany, Japan and Australia, have developed a method for ultra-accurate, fast and high-quality laser processing of halide perovskites (_CH3NH3PbI3) and have shown how to make solar panels of all colors of the rainbow, stamp nanolasers in millions for future optical transistors, quickly record information on the surface that only those to whom it is intended can read. This was reported on April 24, 2020 at FEFU.

Perovskites were first discovered in the first half of the 19th century in the Urals in the form of a mineral consisting of calcium, titanium and oxygen atoms. In the modern world, they attract the interest of scientific groups from all over the world, rapidly gain positions in solar power and photonics, they are used in nonlinear optics, superconductors are created from them.

Organo-inorganic perovskites, with all the advantages, have a serious drawback - they easily break down during processing under the influence of an electron beam, many liquids or high temperatures, losing the properties that scientists are so interested in. This significantly complicates the process of manufacturing functional perovskite nanostructures, which are only tens of nanometers in size, by standard methods, for example, electronic lithography and interferes with the introduction of this material into industry.

Scientists from ITMO University (St. Petersburg) together with colleagues from the Far Eastern Federal University (FEFU, Vladivostok) solved this problem by proposing to process perovskites with ultra-short laser pulses (femtosecond laser). High-quality nanostructures with controlled characteristics were obtained at the output.

"Nanostructuring conventional semiconductors such as gallium arsenide with a powerful pulsed laser is very difficult. Heat scatters in all directions and all the thin, sharp edges are simply eroded by this heat. All the same, as if you try to get a miniature tattoo with subtle details, but because of the paint spread under the skin, you get just an ugly blue spot. Perovskit, on the other hand, has poor thermal conductivity, so our patterns turned out to be clear and miniature, " noted Sergey Makarov, a leading researcher at the New Physics Department of ITMO University

Scribing or cutting perovskite films into separate blocks is actively used in solar cell production technologies, but the process was not very accurate and was quite traumatic for the material, since part of the perovskite in the immediate vicinity of the section lost its properties due to temperature degradation.

The femtosecond laser does not damage the material. The ultra-short pulses of the laser allow not only to cut through the perovskite, but also to print complex structures on its surface in the form of grooves of various shapes several hundred nanometers wide. In this case, all optical properties of the material are preserved.

"Taking into account the peculiarities of the structure, chemical composition and properties of perovskite materials, we have proposed an original technology for their laser processing. To avoid perovskite-damaging effects like overheating, we irradiated it with ultra-short laser pulses. The intensity was selected so that at the points of evaporation of the material the temperature reached the entire 160C0. We managed to remove perovskite evenly and very accurately in a given beam profile of the area without significant negative impact on the surrounding material. The technology has provided unprecedented quality printing of elements, " noted' Alexander Kuchmizhak, researcher at the NTI FEFU Center for to neurotechnologies Technology/' VRAR

Scientists at FEFU and ITMO University named three areas at once where their development can give tangible applied results.

The first is to record information on the perovskite, which can only be read under certain conditions known to the user.

"We demonstrated the applicability of our approach using the example of non-destructive laser printing of diffraction gratings and arrays of microstrip lasers with an extremely small size of only 400 nanometers. Such dimensions will allow in the future to implement active elements for fully optical data transmission lines, " noted Alexey Zhizhchenko, researcher at the Nano-Technology Research Center of the FEFU School of Engineering, one of the developers of the technology

Second, using a laser, you can change the visible color of the perovskite fragment without dye. The material can appear yellow, black, blue, red to the eye, depending on your tasks.

"The laser, in order to give color to the surface, applies special nanostructures with a certain period. This is necessary to create solar panels of all colors of the rainbow. Modern architecture allows you to cover at least the entire surface of the building with solar panels, but not all customers want plain black panels. With the help of color batteries, a skyscraper can be yellow, blue, red and still work with all its walls and roof like a solar battery. Yes, energy efficiency will be less than that of black photocells, but still higher than that of simple walls, " noted Sergey Makarov, a leading researcher at the New Physics Department of ITMO University

The third application is the creation of nanolasers for optical sensors and optical chips, information in which will be transmitted not due to the movement of electrons, but due to the movement of photons.

The simple, fast and cheap production of such elements, according to FEFU scientists, will bring closer a new era of computer technology that will work on the principles of controlled light emission. Processing perovskites using the proposed technology gives a chance to create thousands, even hundreds of thousands of nanolasers per minute. Industrial adoption of the technology will bring the world much closer to the creation of optical computers.

"Another feature of the technology is that it is possible to carry out layer-by-layer thinning of perovskite with high accuracy. This makes it possible to produce three-dimensional perovskite microstructures and more complex forms of light-emitting and optoelectronic devices with expanded functionality. For example, it is possible to manufacture a miniature laser emitting a vortex laser beam necessary for ultra-dense information transmission. It is important that the light-emitting properties of the material remaining after laser evaporation are even improved. This happens because the chemical composition of the surface changes, and with this, defects from laser exposure are passivated, " noted Alexander Kuchmizhak, researcher at the NTI FEFU Center for Neurotechnology, VR/AR Technology

Scientists from FEFU, ITMO University, Joint Institute of High Temperatures (RAS), Institute of Automation and Control Processes (IAPU, FEA RAS), Ruhr University in Bochum (Germany), Tokai University (Japan), Swinburne University of Technology (Australia) took part in the work.

See also

• Optical transistors
• Optical reflectometer