For the reactors used in the manufacture of LED’s there are more promising materials than the ones currently in use, the researchers point out.
There are many new possibilities for the development of gallium nitride (GaN) used in the production LEDs. One of the most promising production methods of gallium nitride is the ammonothermal method which uses a reactor filled up with liquid ammonia. The method is identical with the hydrothermal method utilised in the production of quartz, in which water is used instead of ammonia.
However, the high temperature inside the ammonothermal reactor combined with a pressure 2,500 times the atmospheric pressure and the corrosive effects of the so-called supercritical fluid pose a challenge to the reactor chamber and thus to the manufacture of LED materials. To find a solution to the problem, Aalto University Post-Doctoral Researcher Sami Suihkonen and a research group from the University of California, Santa Barbara led by Nobelist in Physics Shuji Nakamura and Post-Doctoral Researcher Siddha Pimputkar systematically analysed the behaviours of 35 metals, 2 metalloids and 17 different ceramic materials with 3 different supercritical fluid chemistries heated to a temperature of 572 degrees Celsius.
In the ammonothermal method, the energy contained in the reactor corresponds roughly to a stick of dynamite.
– In the ammonothermal method, the energy contained in the reactor corresponds roughly to a stick of dynamite, making the conditions fairly hostile, Sami Suihkonen sums up.
– A nickel-chromium alloy commonly used in the reactors tolerates ordinary supercritical ammonia quite well but poorly withstands the effects of the mixtures used in the production of GaN which include the addition of ammonium chloride or sodium. Our research indicated that vanadium, niobium and tungsten carbide are stable in all three supercritical fluids. For practical applications, however, it is more important to find a material best suited for a certain type of chemistry. For ammonium-sodium this was silver; with ammonium-chloride, silicon nitride and noble metals appear the most promising.
Higher quality materials with applications in power electronics
To replace the reactor’s nickel-chromium alloy with other structural materials would require the reshaping of the manufacturing process according to Suihkonen. More robust reactors would nevertheless enable the production of higher quality GaN containing fewer crystal defects which in turn leads to higher quality LEDs. Better LED quality translates to cheaper price.
– From a high-quality LED more light can be obtained per surface-area unit. As the price of an LED is governed by its surface area, better materials could reduce the price of LEDs to even a fraction of the current price Suihkonen calculates. Moreover, higher quality LED’s generate less heat and thus require smaller cooling elements, which could further reduce the price and enable LED lighting fixtures that are more compact than the current ones.
Apart from their use in more economical and efficient illumination, these better materials could be useful also in power electronics, which is needed among other things, in power control of electric vehicles, in power supplies and converters.
The Latest on: LEDs
via Google News
The Latest on: LEDs
- Three leds in series create a ‘human-centric lighting solution’on April 9, 2021 at 4:15 am
Lumileds has teamed up with NASA spin-out BIOS Lighting to create a "human-centric lighting solution, that delivers superior melanopic ratios at comfortabl ...
- Fungus turns wood piezoelectric, allowing it to power LEDson April 9, 2021 at 4:08 am
Infecting wood with wood-decay fungus can boost its piezoelectric output by 55 times, researchers in Switzerland have discovered. The material scientists found that after 10 weeks of infection, blocks ...
- Now, PLI scheme for ACs, LEDs and solar cellson April 7, 2021 at 6:00 pm
Goyal said the ministry of new and renewable energy will soon issue detailed operational guidelines, specifying selection criteria of companies, rates of incentive available under the scheme etc.
- History Of White LEDson April 7, 2021 at 4:59 pm
Compared to incandescent lightbulbs, LEDs produce a lot more lumens per watt of input power — they’re more efficient at producing light. Of course, that means that incandescent light bulbs ...
- Luminus' New IR LEDs Set New Output Benchmarkon April 7, 2021 at 1:26 pm
Sunnyvale, Calif., April 7 2021, Luminus Devices has expanded its portfolio of ultra-high-power infrared (IR) LEDs with a new product line that addresses the rapid expansion of life sciences, medical, ...
- Too Much of a Good Thing: LEDs on Buildingson April 7, 2021 at 8:50 am
So, LEDs can only lead to more energy use if they lead to more than 2.5x the amount of light being used. More light will be used yes, but not that much more. I assumed 15% more in my calculations ...
- You Can Now Build Your Own Glowing LED D20 (with A Whopping 2,400 LEDs)on April 6, 2021 at 5:00 pm
It was this sacred geometry that [Greg Davill] chose to bless with the glory of glowing RGB LEDs. Now, [Greg] has shared the files so you can build your own. The development blog of the D20 is a ...
- Towards the in vivo detection of cancer progression using circularly polarized LEDson April 6, 2021 at 4:19 pm
This method can be implemented using an endoscope equipped with spin-LEDs—devices that emit circularly polarized light. Most cancers of the digestive system emerge in the surface layer first and ...
- Isamu Akasaki, 92, Dies; Nobel Winner Lit Up the World With LEDson April 6, 2021 at 2:45 pm
A physicist, he shared the prize with two others for their breakthrough in creating blue light-emitting diodes, succeeding “where everyone else had failed.” ...
- Global ROY LEDs Sales Market 2021: Size, Shares, Top Countries Records, Industry Outlook, Driving Factors By Manufacturers, Growth and Forecast 2027on March 29, 2021 at 10:40 pm
Global “ROY LEDs Sales Market" Research Report 2021-2027: ROY LEDs include red, orange, and yellow LEDs. Compared with ...
via Bing News