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Greenest green

Chemical engineers create the greenest green for LED displays


A team of chemical engineers at Swiss University has generated an ultra-pure green LED that could pave the way for improved Ultra-HD.

In order to produce the next generation of ultra-high resolution TV and smartphone displays, it is first necessary to create light emitting diodes that give off ultra-pure red, blue and green colors. This has already been achieved for red and blue, but because the eye is able to distinguish a greater number of green hues than red or blue ones, producing and ultra-green LED has proven impossible. Until now. A chemical engineering team at ETH Zurich University, led by Professor Chih-Jen Shih has succeeded in generating an ultra-pure green light for the first time.

Colors are created through a mixture of red, blue and green. The purer these primary colors, the broader the range of hues a screen can display. The new green LED is between 97 to 99 percent pure, when compared to the standard. By comparison, currently available displays use colours which are on average only around 75 percent pure. Until now, high-temperatures were required to produce pure light with LED technology, but the new LED can be created using simple room-temperature processes. This could allow low-cost production of the purer LED.

We have already seen how nanomaterials have been used in energy generation and to aid in the large-scale production of quantum chips. Similarly, Shih and his team have used inexpensive, efficient nanomaterials from solar cells in developing their LEDs. Because the crystals used in the green LED are just 4.8 nanometres thick, the diode is ultra-thin and as bendable as a sheet of paper. It will still be some time, however, before we see the first industrial application of ultra-green light-emitting diodes. The LED first need to be made more efficient when converting electricity into light, and needs to have a much greater lifespan. Once this is achieved, how might the pure green LED transform TV and smartphone displays?




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