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The first LED was created by Soviet inventor Oleg Losev [9] in 1927, but electroluminescence was already known for 20 years, and relied on a diode made of silicon carbide. ...
An organic light-emitting diode (OLED), also known as organic electroluminescent (organic EL) diode, [1] [2] is a type of light-emitting diode (LED) in which the emissive electroluminescent layer is an organic compound film that emits light in response to an electric current.
LED development began with infrared and red devices made with gallium arsenide. Advances in materials science have enabled making devices with ever-shorter wavelengths, emitting light in a variety of colors. LEDs are usually built on an n-type substrate, with an electrode attached to the p-type layer deposited on its surface.
Gallium nitride (Ga N) is a binary III/V direct bandgap semiconductor commonly used in blue light-emitting diodes since the 1990s. The compound is a very hard material that has a Wurtzite crystal structure.
LED phosphors can be placed directly over the die or made into a dome and placed above the LED: this approach is known as a remote phosphor. [27] Some colored LEDs, instead of using a colored LED, use a blue LED with a colored phosphor because such an arrangement is more efficient than a colored LED. Oxynitride phosphors can also be used in LEDs.
Water molecules have been detected on the surface of asteroids for the first time, proving that these remnants from the formation of our solar system aren’t just dried-up space rocks.
A single LED can have several phosphors at the same time. [89] [99] Some LEDs use phosphors made of glass-ceramic or composite phosphor/glass materials. [100] [101] Alternatively, the LED chips themselves can be coated with a thin coating of phosphor-containing material, called a conformal coating. [102] [103]
Lewis structure of a water molecule. Lewis structures – also called Lewis dot formulas, Lewis dot structures, electron dot structures, or Lewis electron dot structures (LEDs) – are diagrams that show the bonding between atoms of a molecule, as well as the lone pairs of electrons that may exist in the molecule.