MOSCOW, 22 Aug. UrFU scientists as part of an international research team managed to double the brightness of perovskite LEDs. According to the researchers, their development will make the production of such LEDs much easier and cheaper than today's common organic light sources used in many modern screens. The results are published in Advanced Science.
LEDs are semiconductor devices that emit light when current flows through them. Light is generated as a result of electroluminescence — a process by which it is possible to obtain radiation in a narrow range of wavelengths, that is, a single color. The screens of various devices use diodes that emit red, blue and green light, by mixing which you can get all the colors perceived by the human eye.
To date, most LEDs in matrix display devices, such as phone screens, laptops and televisions, are made on the basis of organic substances. The technology of their manufacture is laborious and costly. At the same time, for example, the durability of blue is much less than green and red, the scientists said. Therefore, many research groups around the world are developing LEDs based on alternative, cheaper and more stable materials.
A team of scientists from the Ural Federal University named after the first President of Russia B.N. Yeltsin (UrFU) and the National Taiwan University created a green LED based on perovskites — promising materials for solar energy and photonics.
«One of the main advantages of perovskite LEDs is the simplicity of their synthesis: they are obtained from a solution that practically finished form. Therefore, they are cheaper and technologically easier to manufacture,» explained Ivan Zhidkov, head of the Ural Federal University's laboratory of photovoltaic materials, co-author of the publication.
According to developers , Perovskite LEDs have high stability and long service life. However, they lack brightness, which depends on the efficiency of electron transfer from their source to the semiconductor mineral. Researchers have solved this problem.
«The structure of an LED can be thought of as a path from one point to another. For the interaction of these points with each other, a good» path «is needed. We have developed a good» road surface «which smoothes out defects at the layer boundaries and provides a stable current of electrons. They enter the perovskite and , connecting with positive charge carriers, cause a green glow,» said Zhidkov.
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To improve the characteristics of the radiation source, scientists used a quasi-2D layer of perovskite — the thinnest film of material with a large surface area. A layer of a polymer material 1 atom thick was placed on it, which ensures the transport of charge carriers from the electron-conducting layer to perovskite.
According to the researchers, they have developed a technology for applying a monolayer to a perovskite film, which slightly complicates the technology for manufacturing an LED as a whole.
In the future, the team plans to achieve even brighter green diodes and apply new technology to create efficient red and blue LEDs.
UrFU Photovoltaic Materials Laboratory was created with the financial support of the state program of strategic academic leadership «Priority 2030».