The hottest researchers promote the efficiency of

2022-08-08
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Researchers promote that the efficiency of perovskite LED is comparable to OLED

compared with OLED widely used in high-end consumer electronics products, perovskite based LED developed by researchers at Cambridge University can be manufactured at a lower cost, and can be adjusted to emit light in visible light and near- Infrared spectrum with high color purity. Now, researchers have set a new efficiency record for LED based on perovskite semiconductor, which is comparable to * organic LED (OLED)

researchers designed the calcium titanium layer in the led to display nearly 100% internal luminous efficiency, opening up the future applications of display, lighting and communication, as well as the next generation of solar cells

these perovskite materials are the same as those used to manufacture high-efficiency solar cells, and may one day replace commercial silicon solar cells. Although perovskite based LEDs have been developed, they are not as effective as traditional OLEDs in converting electrical energy into light

as early as four years ago, the early hybrid perovskite LEDs developed by Professor richardfried's team in the Cavendish Laboratory of the university are promising, but the loss of calcium titanium deposits caused by tiny defects in the crystal structure limits their luminous efficiency

now, Cambridge researchers and their collaborators from the same group have shown that by forming perovskite composite layers with polymers, higher luminous efficiency can be achieved, close to thin-film OLED, while the average value-added in China is only 0.4 times the theoretical efficiency limit. Their findings were published in the journal Nature photonics

"this perovskite polymer structure effectively eliminates non emission losses, which is * times achieved in perovskite based equipment," said Dr. Dawei Di of Cavendish Laboratory in Cambridge, one of the corresponding authors of the paper. "By mixing the two, we can basically prevent electrons and positive charges from passing through the first direction: environmentally friendly plastics came into being and regrouped through defects in perovskite structures."

perovskite polymer blends for LED devices, called bulk heterostructures, are made of two-dimensional and three-dimensional perovskite components and insulating polymers. When the ultrafast laser irradiates the structure, the charge pair carrying energy moves from 2D region to 3D region at the speed of one trillion of a second: it is much faster than the early layered perovskite structure used in LED, except for the establishment of a new material research and development center. Then, the separated charges in the 3D region recombine and emit light very effectively

"because the energy transfer from 2D region to 3D region occurs so fast, and the charge in 3D region is isolated from the defect of polymer, these mechanisms can prevent defects and thus prevent energy loss."

"Under the current density related to display applications, the external quantum efficiency of these devices is higher than 20%, creating a new record for perovskite LEDs, which has a similar efficiency value to OLEDs in the current market," said Baodan Zhao, the * author of the paper

although perovskite based LEDs have begun to compete with OLEDs in efficiency, they still need better stability if they are to be used in consumer electronics. When perovskite based LEDs were first developed, their lifespan was only a few seconds. The half-life of the LED developed in the current research is close to 50 hours, which is a huge progress in just four years, but it is still far from reaching the life required for commercial applications, which will require an extensive industrial development plan. "Understanding the degradation mechanism of LED is the key to future improvement."

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