LED - Page 9

A research team, led by Professors Byungsoo Bae at KAIST and Taewoo Lee at Seoul National University, has developed a new perovskite light-emitting diode (PeLED) display material.

PeLED is a type of LED that uses perovskite as a light-emitting material. Currently, the production cost is lower than that of organic light emitting diodes (OLEDs) and quantum dot light emitting diodes (QLEDs), and it has the advantage of enabling sophisticated color realization.

Perovskite-Info is proud to present our first market report, The Perovskite for the Display Industry Market Report. This market report, brought to you by the world's leading perovskite and OLED industry experts, is a comprehensive guide to next-generation perovskite-based solutions for the display industry that enable efficient, low cost and high-quality display devices.

Reading this report, you'll learn all about:

• Perovskite materials and their properties
• Perovskite applications in the display industry
• Perovskite QDs for color conversion
• Prominent perovskite display related research activities

The report also provides a list of perovskite display companies, datasheets and brochures of pQD film solutions, an introduction to perovskite materials and processes, an introduction to emerging display technologies and more.

India-based researchers have recently designed a novel synthesis procedure that can produce highly uniform luminescent perovskite nanocrystals with uncommon shapes and surface morphologies.

Their work broadens the range of strategies that can be used for tuning the optical and photonic properties of these materials, which are widely studied for use in solar cells, light-emitting diodes, and electronic displays.

Organic-inorganic hybrid perovskites (OIHPs) have great potential for various applications like solar cells, lighting-emitting diodes (LEDs), field effect transistors (FETs) and photodetectors. Among their most important parameters influencing the power conversion efficiency (PCE) of devices based on perovskite materials is their carrier mobility. However, despite massive progress made by introducing new components into the structure to control the mobility of the carriers, the understanding on the atom level of how the components affect the performance is still lacking.

To address this problem, a research team led by Prof. Luo Yi and Prof. Ye Shuji from the University of Science and Technology of China (USTC) of the Chinese Academy of Sciences (CAS) has synthesized a series of 2D OHIPs films with large organic spacer cations.

Researchers at The University of Cambridge and Zhejiang University recently created highly efficient LEDs by depositing mixed-dimensional perovskites on a thin lithium fluoride interface. The fabrication method they used reportedly resulted in LEDs with impressive external quantum efficiencies, while also enabling the deposition of perovskites on a material that they are typically incompatible with.

Image from Nature Electronics

The researchers have been conducting research into perovskite-based LEDs for a few years now. Back in 2018, they created a near-infrared LED using perovskite-polymer heterostructures that achieved external quantum efficiencies of over 20% and internal quantum efficiencies of almost 100%.

A team of researchers at the Ulsan Institute of Science and Technology (UNIST) and Korea University, led by Professors Myung-Hoon Song, Sang-Gyu Kwak and Han-Young Woo, recently announced the development of a PeLED - a perovskite-based LED device, that emits blue light.

The team explained that the perovskite light emitting device, which uses perovskite as a color material, is more than three times more efficient than before and has a high color purity, enabling a clear blue color.

Researchers at Northwestern University have developed a new method for synthesizing halide perovskite nanocrystals.

The synthesis process for the halide perovskite nanocrystal arrays. Image from Science Advances

'This method could be used to create optical displays with 'true' reds, greens, and blues that completely outshine current LEDs,' said Northwestern's Chad A. Mirkin. 'From color purity to pixel density, these nano-LEDs point toward a potentially dramatic improvement over current LEDs.'

NUS researchers have developed transparent, near-infrared perovskite light-emitting diodes (LEDs) that could be integrated into the displays of smart watches, smart phones and augmented or virtual reality devices.

a A transparent PeLED overlaid across a smart-watch display to show high optical transparency and neutral color. b Near-infrared photo showing bright NIR electroluminescence from the transparent PeLED above the smart-watch display. Image from article

These transparent devices are constructed with an ITO/AZO/PEIE/FAPbI₃/poly-TPD/MoO₃/Al/ITO/Ag/ITO architecture, and offer a high average transmittance of more than 55% across the visible spectral region.

Research using the Canadian Light Source (CLS) at the University of Saskatchewan could help bring perovskite QDs display technology closer to commercilization.

Quantum dots are nanocrystals that glow, a property that scientists have been working with to develop next-generation LEDs. When a quantum dot glows, it creates very pure light in a precise wavelength of red, blue or green. Conventional LEDs, found in TV screens today, produce white light that is filtered to achieve desired colors, a process that leads to less bright and muddier colors.

A recent research by Barry Rand, associate director for external partnerships and associate professor of electrical engineering and the Andlinger Center for Energy and the Environment, with a team of researchers, has advanced perovskite-based LEDs by significantly improving the stability and performance by better managing the heat generated by the LEDs.

The research identifies several techniques that reduce the accumulation of heat within the material, which extended its lifetime tenfold. When the researchers prevented the device from overheating, they were able to pump enough current into it to produce light hundreds of times more intense than a typical cell phone display. The intensity, measured in watts per square meter, reflects the real amount of light coming from a device, uninfluenced by human eyes or the color of the light. Previously, such a level of current would have caused the LED to fail.