Welcome to LEDnetics.com, your reference LED store for all lighting and LED devices. In electronics the LED (abbreviation of Light Emitting Diode) is an optoelectronic device that exploits the ability of some semiconductor materials to produce photons through a phenomenon of spontaneous emission when crossed by an electric current. In lighting technology, the LED is a high-efficiency technology that guarantees excellent energy savings.

The commercial strength of these devices is based on their ability to achieve high brightness (many times greater than that of tungsten filament lamps), low price, high efficiency and reliability (the life of an LED is one to two orders of magnitude higher than that of classic light sources, especially under conditions of mechanical stress). LEDs work at low voltage, have high switching speed and their construction technology is compatible with that of silicon integrated circuits.

The first LED was developed in 1962 by Nick Holonyak Jr.. In 2014 the Nobel Prize for Physics was awarded to Isamu Akasaki and Hiroshi Amano from the University of Nagoya and Shūji Nakamura from the University of California, Santa Barbara for research on blue light LED. In the 1990s, LEDs were produced with ever higher efficiency and in an ever-increasing range of colors, also producing white light. At the same time, the amount of light emitted has increased to levels that are competitive with ordinary light bulbs.

Use in lighting

LEDs are increasingly used in the lighting industry to replace some traditional light sources. Their use in domestic lighting, thus replacing incandescent, halogen or compact fluorescent lamps (commonly called energy-saving because they have a higher yield), is now possible with remarkable results, achieved thanks to the innovative techniques developed in the field.

At the beginning of the research, the luminous efficiency, quantity of light/consumption (lm/W), was calculated in the minimum ratio of 3 to 1, then it has improved a lot. The limit of the first devices suitable to be used in this type of application was the insufficient amount of light emitted (luminous flux expressed in lumens). This problem was overcome with the latest generation models, combining the increase in efficiency with the technique of having die matrices in the same package connected in series and parallel or making the matrix directly in the substrate of the device. The efficiency of current devices for professional and civil use is more than 120 lm/W, but it drops to around 80 lm/W in warmer light devices. For example the Cree CXA3050 has Ra>90 and 2700K. A 60 W incandescent lamp powered at 220V, emits a luminous flux of about 650 lumens.

As a comparison, an incandescent lamp has a luminous efficiency of about 10-19 lm/W, while a halogen lamp about 12-20 lm/W and a linear fluorescent lamp about 50-110 lm/W. A lower ease of use in functional lighting compared to traditional lamps is constituted by the characteristics of power supply and dissipation, which strongly affect the light output and duration over time. However, it becomes difficult to identify direct relationships between the various sizes, between which also comes into play a further parameter, namely the beam angle of light emission, which can vary from about 4 degrees to over 120 degrees, however, can be modified through appropriate lenses placed frontally.

LED manufacturers are manufacturers of semiconductors, silicon factories, while bulbs are mainly produced by other manufacturers. There is, therefore, a certain delay between the date of placing a new LED device on the market and the availability on the market of a bulb that uses it.

The advantages of LEDs from a lighting point of view are:

  1. Operating time (high emitting LEDs reach about 50,000 hours with a loss of luminous flux of 10% max);
  2. reduced maintenance-replacement costs;
  3. high efficiency (when compared to incandescent and halogen lamps) Light without IR and UV components (high efficiency: no part of the energy transformed into light is outside the visible spectrum);
  4. easy realization of efficient plastic optics;
  5. flexibility of light spot installation;
  6. possibility of a strong spot effect (near-point source);
  7. safe operation because of very low voltage (normally between 3 and 24 Vdc);
  8. cold start (down to -40 °C) without problems;
  9. absence of mercury;
  10. possibility to create luminaires of new shape due to the reduced dimensional impact;
  11. possibility to adjust the luminous intensity (only on some models);
  12. less heat generated in the environment compared to other lighting technologies.

Bestselling Products

 

DAYBETTER Led Strip Lights 100ft (2 Rolls of 50ft) Smart Light Strips with App Control Remote, 5050 RGB Led Lights for Bedroom, Music Sync Color Changing Lights for Room Party

  • Smart app control, ir remote control: The 100 feet led strip lights support both app apollo lighting and 24 keys ir remote for control, which allow you change the led lights color and modes are conveniently for bedroom, ceiling, kitchen, living room, bar and party decoration
  • Easy installation: The led strip lights 100 feet, 2 rolls of 50 feet, ultra long is enough to reach around your entire bedroom and light up the whole home for party, wedding indoor
  • Music sync: Led lights strip with built in sensitive microphone, this ambience Lights color changing sync to music, make your party up to the high peak, light up your life and makes life more colorful and wonderful
  • Smart timing settings: With timer function, the rgb led strip lights allow you to pre set time to turn on off led lights and change color at certain times, just enjoy it in a smart way
  • Led lights features: Our 5050 rgb led chips allows the led lights to be very colorful and durable; The remote can dim the led light strip and offer different colors and modes by remote
 

65.6ft Led Lights for Bedroom dalattin Led Strip Lights Color Changing Lights with 44 Keys Remote,2 Rolls of 32.8ft

  • 65.6feet Led Lights:Long enough to reach around your entire room and light the whole place up
  • Cuttable and Linkable:Led lights can be cut between every 3 LEDs along the cutting marks;Note that our products do not include connectors
  • Self Adhesive: 3M self adhesive tape of led lights can be flexible stuck on any dry and flat surface
  • Widely Use:Suitable for living room,kitchen,cabinet,porch,bar,bedroom,party,Christmas or wedding
  • Before you want to stick the light,please confirm its position to avoid damaging your wall
 

50ft Led Lights for Bedroom, Keepsmile APP Control Music Sync Color Changing Led Light Strips Led Strip Lights with Remote for Room Home Decoration

  • Smart App&Music sync:RGB LED strip lights 50ft can freely control thousands of colors through 44-key infrared remote control or smartphone APP.Adjustable brightness and multiple lighting modes to fit room mood.Built-in sensitivity adjustable microphone,the led strip lights dances to the ambient sound;make your party up to the high peak
  • Timer mode: The bluetooth strip light has a smart Timer mode,Pre-setting the appropriate time and suitable color to make it turn on /off automatically,it can be used as an lights alarm clock,you wake up in romantic lighting
  • Easy Installation: LED light strips self-adhesive tape can firmly adhere to any dry and smooth surface,solve the problem of falling light strips; We recommend you test the lights before installation.(Note:Before sticking the light strip, please confirm its position,Avoid secondary pasting)
  • Cuttable and linkable: You can customize the length of the LED lights, cutting every 3 LEDs along the cutting mark.You can also use a specific connector to extend the light bar to other places
  • Widely use: LED strip lights is long enough;Easily decorate places like bedroom,ceiling,kitchen,stairsparty,wedding,windows,living room, party, back of tv, bar.Suitable for holiday parties,like Christmas,Halloween and Easter
 

Tenmiro 65.6ft Led Strip Lights, Ultra Long RGB 5050 Color Changing LED Light Strips Kit with 44 Keys Ir Remote Led Lights for Bedroom, Kitchen, Home Decoration

  • Ultra Long Strip Lights: 65.6ft led strip lights are long enough to reach around your entire room and light the whole place up, cuttable design allows you to adjust the length of led lights whatever you like, for bedroom, living room, cabinet, party, christmas, etc
  • Multi Color and Diy: Led lights colorful and durable, the brightness of the lights strip can be adjusted and offer millions different colors and 8 lighting modes(jump, fade, flash etc) by 44keys remote
  • Easy Installation: Complete led light strip kit Including 4 rolls of 16.4ft led light strips, power adapter, 44keys remote Control, controller, instruction manual, led strip lights installation accessories(4 pin connectors, gapless solderless connectors, back adhesive hooks), no need for other devices, self adhesive tape easy to install
  • Cuttable and Linkable: The led lights can be easily cut and linked with other strip led lights, which can be cut every 3 leds along the cutting marks, you can also customize the length of the led lights, while arrows of the lights should be faced to each other when connecting, if using solderless connecto then while '+12V' should be faced to each other when connecting
  • Multiple Scenes Available: Rgb led strip lights is a suitable house ornament, transforms your home, kitchen, ceiling, back of tv, desk, stairs, bar and more with color changing lights
 

Led Zeppelin: Dazed and Confused

  • Amazon Prime Video (Video on Demand)
  • Jimmy Page, Robert Plant (Actors)
  • Brian Aabech (Director) - Brian Aabech (Producer)
  • English (Playback Language)
  • English (Subtitle)
 

MINGER LED Strip Lights 16.4ft, RGB Color Changing LED Lights for Home, Kitchen, Room, Bedroom, Dorm Room, Bar, with IR Remote Control, 5050 LEDs, DIY Mode

  • Multicolor changing: the RGB LED strip lights kit has not only RGB(Red, Green, Blue), 16 multicolored options, but also DIY selection
  • Remote control: 44-key IR remote allows you to choose colors, adjustable brightness and multiple lighting modes to fit room mood. (remote range: 10m)
  • Bright LED Lights: it features 150 bright 5050 LEDs that easily light up a room, bedroom, dorm room, kitchen countertop. Suitable for birthday party, home gathering
  • Easy to install: with back adhesive and flexible strip design, it can stick on any dry and flat surface. Note: use the packaged adapter to meet working power requirement
  • Notice for using: please do not roll up when using it to avoid whole strip getting overheated. The strip is non-waterproof for indoor use only
 

65.6ft Led Lights for Bedroom, Reemeer Led Strip Lights Music Sync Color Changing Led Lights with App Control and Remote, Led Light Strips Used for Party, Home Decoration

  • Smart App&Music sync: 3 ways to control your LED Lights, easy to control the strip lights by remote, controller and the application "Lotus Lantern". LED light strips have smart music mode, built-in sensitivity adjustable microphone, which can create a romantic, relaxing and cheerful party ambiance with music. The LED strip light can dance to the ambient sound.
  • Upgraded Strong Self-Adhesive: The lights strip has upgraded adhesive so it can stick very well on the dry & smooth surface. LED lights strip self-adhesive tape can firmly adhere to any dry and smooth surface, solving the problem of falling strip lights. We recommend you test the light before installation. (Note: Before sticking the light strip, please confirm its position, avoid secondary pasting).
  • Timing LED Light Strips: With the smart application, the light strips can automatically turn on and off through preset time. 28 dynamic modes and DIY color options available for you to choose, so you can select or define your own color. The 65.6ft Led lights can reach around your entire room and light up the whole place. (Note: The rgb lights are NOT waterproof).
  • Easy to Use and Install Led Strip Kit: A complete Led lights strip kit includes 4 rolls of 16.4ft Led strips, an AC power adapter, a remote control and a controller. Smart Led strip lights are perfect for home decoration. These led strips give a warm and romantic atmosphere to dining rooms, bedrooms, staircases, doorways, computers, desks, corners, bars, meeting rooms and living rooms,making you feel relaxed and happy.
  • Cuttable and Linkable: This led room lights can be easily cut and linked with other light strips to get your desired length, which can be cut every 3 Leds along the cutting marks also use a specific connector to extend the light strips to other places. You can DIY the length of the Led lights for room, while arrows of the lights should be faced to each other when connected.
 

Govee LED Strip Lights, 32.8FT RGB LED Lights with Remote Control, 20 Colors and DIY Mode Color Changing LED Lights, Easy Installation Light Strip for Bedroom, Ceiling, Kitchen (2x16.4FT)

  • Colors That Energize: The LED strip lights are packed with traditional RGB and 16 other colors. You can enjoy 6 additional DIY colors for more creative freedom. Jazz up your romantic dinners or Christmas parties with vibrant lighting.
  • Dual Control: Manage your lights easily from the comfort of your couch with a remote control range of 32.8ft. With the control box, you can power the lights on/off, adjust brightness, or change colors at the touch of a button.
  • Adjustable Brightness: 6 brightness levels allow you to alter the strip lights from warm to bright. 5050 LEDs and a 50,000-hour product lifespan ensure you vivid, long-lasting lighting, great for your TVs, bedroom, and kitchen.
  • 32.8ft LED Lights: With 2 rolls of strip lights (16.4ft each) stretching to a total length of 32.8ft and 300 LEDs, you'll find it easy to illuminate larger spaces with bright, colorful lighting during the holidays, parties, or movie nights.
  • Easy to Install: Use the strong adhesive to install the lights to any dry, clean surface, or the clips for further reinforcement. DIY fans will enjoy our cuttable design, allowing you to trim the strips to your liking (4-pin connectors not provided).
 

100ft Led Lights for Bedroom, XIER APP Control Music Sync Color Changing Led Light Strips Led Strip Lights with Remote for Room Home Decoration

  • APP CONTROL: You can freely control the color changing lights with 16 million colors, experience the timing function, 28 Dynamic modes, you can also DIlY your unique color
  • MUSIC SYNC: The strip lights has a smart music mode, lights color will chang with the rhythm of the sound and music, sensitivity adjustable microphone. Applicable for create romantic, relaxed and party atmosphere
  • ULTRA LONG: 100ft led strips are long enough to reach around your entire room and light the whole place up
  • CUTTABLE: Cuttable design allows you to adjust the length of light strip however you like, if you don't need such a long lights, you can be cutted between every 3 LEDs
  • EASY TO INSTALL: No need for any other devices,simply stick the strip lights on clean, dry surface. start to enjoy strip lighting
  • WIDELY USED: Led strip lights are suitable for bedroom, kitchen, cabinet, upstairs, living room and parties
 

Led Zeppelin IV

  • Amazon Prime Video (Video on Demand)
  • Bob Carruthers (Director)
  • English (Playback Language)
  • English (Subtitle)
 

DAYBETTER Led Strip Lights 32.8ft 5050 RGB 300 LEDs Color Changing Lights Strip for Bedroom, Desk, Home Decoration, with Remote and 12V Power Supply

  • Strong self adhesive: The led strip lights has a stronge self adhesive so they stick very well on TVs, cars, cabinets and walls; Please test the led strip lights before installation, every roll lights has one connector to link with controller box, so they should be attached in parallel, not in series
  • Colorful and durable: The infrared remote can adjust multiple colors, including rgb, white, 16 other colors and their brightness; With 6 dynamic modes (auto, flash, jump3, jump7, fade3, fade7) and 2 speed modes (quick, slow) by remote, you can make the light strip show varieties of different color changes; Use the DIY buttons to save 6 colors if you like
  • Cuttable and linkable: Our 32.8 feet led lights strip have 300 leds, it can be cut every 3 LEDs along the cutting marks if you don't need such a long lights or you could extral connectors to extend the lights for your bedroom, TV, desk, computer indoor
  • Remote contol: You can use the infrared remote control to remotely control the light strip to suit the mood of the room easily; You can set it according to different scenes until you are satisfied
  • Widely use: The led lights are suitable for bedroom, kitchen, cabinet, car, living room, party or wedding
 

Govee LED Strip Lights 16.4ft Waterproof Color Changing Light Strips with Remote, Bright 5050 and Multicolor RGB LED Lights for Room, Bedroom, Kitchen, Yard, Party, Christmas

  • Water-Resistant Design: The strip lights are equipped with a clear, silicone coating, protects them from moisture. The coating also helps colors spread evenly, providing you smoother lighting effects.(Note: adapter is not waterproof)
  • Control Remotely: Power your strip lights on/off, increase brightness, and select desired colors at the touch of a button. Thanks to the remote controller, managing your LED room lights within a 10m/32.8ft range is a breeze.
  • Multiple Colors: Led strip lights with 44 key remote controller, provide the primary red, green, blue (RGB) and white, and also 16 multicolored options to DIY your favorite color to decorate your room.
  • Create Your Scene: Stretching to 16.4ft, led lights were designed for multiple scenarios, long enough for bedrooms, bars, countertops, and balconies, and bright enough to illuminate entire areas with vibrant colors.
  • Install with Ease: Using the provided fixing clips and adhesives, simply attach the light strip to any dry, clean surface for use. The lights are cuttable, granting you more creative freedom during installation. (Note: Connectors not included)
 

DYLYNA Led Strip Lights 50ft, Music Sync Color Change Led Lights for Bedroom,5050 SMD RGB Led Light Strips with Remote App Control Led Lights for Room Party

  • 50ft Led Strip Lights: Our led strip lights allow to be controlled via app, controller and 23 keys remote, providing 16 million colors and 28 dynamic modes by downloading the app "Happylighting", making you freely create your favorite ambience.
  • Music Sync Led Lights Strip: With music mode and sensitivity built in mic, lights color will change when they feel the music beats or the sound, making your party and home warmer and more romantic.
  • Timing Led Lights: Rgb led light strip allow to preset the time to automatically turn on or off. You can customize any level of brightness to create your ambience. The led lights can remember the last settings to make you without setting repeatedly.
  • Easily Installation: The led lights can be cut along the cutting mark to make you get the ideal length. Our led lights are sticky, Just remove the adhesive and stick it on a smooth and clean surface,making you not experience the strip falling.
  • Widely Application: Rgb light strips are suitable for your Bedroom, Kitchen, TV, Living rooms, Computer desk, Upstairs, Holidays, Parties and more, beautifying your life. It's also a cool gift for your family and friends.
 

Led Zeppelin - Physical Graffiti: A Classic Album Under Review

  • Amazon Prime Video (Video on Demand)
  • Led Zeppelin (Actor)
  • Sexy Intellectual (Director)
  • English (Playback Language)
  • English (Subtitle)
 

100 Pieces Clear LED Light Emitting Diodes Bulb LED Lamp, 5 mm (Multicolor)

  • 5 mm LED lamp assorted kit: contains 100 LEDs of 10 colors (yellow, orange, emerald green, blue, white, red, green, warm white, purple and colorful flash)
  • Head type: water drop shape round and clear heads; Forward voltage: R/ Y/ G/ O 1.8-2.0 V; B/ W/ WW/ E/ P 3.0-3.2 V; C 3.0-3.4 V; Max. Current: 20 mA
  • Application: not only can they be applied to industrial segment, but also use in some students' experiment, school science, little LEDs are good for doing projects
  • Good repair replacement: the mini diodes are convenient for DIY and repair equipment and electrical appliances, circuit unit; You can use these to make LED glow stick
  • Mini LED diodes with bright light: they are very bright and vibrant colors make them look beautiful at night; You can assemble different color LED diodes as you want
 

Led Zeppelin: The Song Remains the Same

  • Amazon Prime Video (Video on Demand)
  • John Bonham, John Paul Jones, Jimmy Page (Actors)
  • Peter Clifton (Director) - Peter Grant (Producer)
  • English (Playback Language)
  • English (Subtitle)
  • Audience Rating: PG (Parental Guidance Suggested)
 

A to Zeppelin: The Story of Led Zeppelin

  • Amazon Prime Video (Video on Demand)
  • John Bonham, Jimmy Page, Robert Plant (Actors)
  • Hector De Leon (Director) - G.B. Sidson (Writer) - Mark McLaughlin (Producer)
  • English (Playback Language)
  • English (Subtitle)
 

Led Zeppelin I (Remastered Original Vinyl)

  • Side 1
  • 1. Good Times Bad Times
  • 2. Babe I'm Gonna Leave You
  • 3. You Shook Me
  • 4. Dazed And Confused
 

LED Controller

  • Connect to bluetooth device
  • Turn ON LED
  • Turn OFF LED
  • Basic tutorial to for interfacing bluetooth with arduino
  • English (Publication Language)
 

Product-Led Onboarding: How to Turn New Users Into Lifelong Customers

  • Amazon Kindle Edition
  • John, Ramli (Author)
  • English (Publication Language)
  • 06/08/2021 (Publication Date) - ProductLed Press (Publisher)

History of LED

The first devices

In 1907, at the Marconi Company laboratories, Henry Joseph Round discovered the effect of photoluminescence using silicon carbide (SiC) and a radio component. Exactly twenty years later, Oleg Losev published a theory in Russia, where he claimed to have created the equivalent of a rudimentary LED; although the publication was also published in the German and British Empires, for decades there were no practical applications for his invention.

In 1936, at Marie Curie’s laboratories, physicist Georges Destriau obtained electroluminescence (which he himself called “Losev light”) by encapsulating zinc sulfide (ZnS) in a container in which he applied an alternating electric field. Three years later, the Hungarians Zoltán Bay and György Szigeti patented a silicon carbide device capable of emitting white or white light tending to yellow or green, depending on the impurity present. In 1951, Kurt Lehovec, Carl Accardo and Edward Jamgochian understood for the first time the real functioning of a diode capable of emitting light, using silicon carbide crystals and as an electrical source a battery and a pulse generator, comparing in the following two years the results obtained with others obtained by varying the type of crystals and their purity.

In 1955, Rubin Braunstein, of the Radio Corporation of America, obtained infrared light emission from gallium arsenide (GaAs) and other semiconductors, such as gallium antimonide (GaSb), indium phosphide (InP) and silicon germanide (SiGe), both at room temperature and 77 kelvin. Two years later, he demonstrated that rudimentary devices could be used to communicate over short distances; such devices would then be used in optical communications.

In September 1961, at Texas Instruments, James R. Biard and Gary Pittman discovered that a tunnel effect diode with gallium arsenide substrate was capable of emitting infrared light with a wavelength of 900 nanometers. In October, they demonstrated the effectiveness of communication between this diode and an electrically isolated photodetector. On August 8, 1962, Biard and Pittman applied for a patent entitled “Semiconductor radiant diode”: a diode with a p-n junction and diffuse zinc, with the cathode spaced to allow an efficient emission of infrared light when the device is in the so-called direct polarization. After receiving applications also from General Electric, Radio Corporation of America, IBM, Bell Laboratories and MIT Lincoln Laboratory, the U.S. patent office gave the two inventors the patent for the infrared light emitting diode in gallium arsenide, the first real LED for practical use. Immediately afterwards, Texas Instruments launched a project for their realization and, in October 1962, the company announced the commercial production of LEDs with gallium arsenide crystalline structure capable of emitting light with a wavelength of 890 nanometers.

The first emission LED in the visible spectrum was developed at General Electric by Nick Holonyak Jr. who published an article on December 1, 1962. Having obtained an LED with emission in the visible spectrum, then the realization for the first time of an electronic component capable of emitting light perceptible by humans, made Holonyak to the public eye as the “father” of the LED. In 1972, George Craford, a former student of Holonyak, created the first yellow light LED and improved the light output of red and red-orange LEDs by a factor of ten. Four years later, T. P. Pearsall created the first high efficiency and luminescence LED, resulting in new semiconductor compounds specifically suitable for fiber optic transmissions.

Mass Use

The first commercial LEDs were used to replace some incandescent and neon lamps, for seven-segment displays, optoisolators, expensive laboratory equipment first and then to switch to calculators, televisions, radios, phones and more. Both infrared and visible LEDs were still extremely expensive, however, in the order of two hundred dollars each, so they were used relatively little. Starting in 1968, Monsanto Company was the first in the world to start mass production of LEDs in the visible, using gallium, arsenic and phosphor to make red LEDs suitable as indicators (arrows, numbers, etc.). Later, other colors began to be available and LEDs began to appear on various other equipment and devices. In the seventies, LED devices were produced and marketed for less than five cents each. These diodes were made from semiconductor chips manufactured with the planar growth process devised by Jean Hoerni at Fairchild Semiconductor. The combination of this process with innovative encapsulation methods enabled Fairchild, under the leadership of optoelectronics pioneer Thomas Brandt, to significantly reduce production costs, opening the way for all other manufacturers.

The first LEDs had a metal casing similar to that used for transistors, with a glass lens for the passage of photons. Subsequently, they switched to transparent plastic casings, of various shapes and often with colors corresponding to the color of the light emitted. In the case of infrared LEDs, the tint can be applied to achieve the opposite effect, i.e. blocking the visible light output. Specific encapsulations are then designed for the efficient heat dissipation of high power LEDs.

The advent of blue LEDs

The first blue-violet LED was made with gallium nitride (GaN) doped with magnesium at Stanford University in 1972 by Herb Maruska and Wally Rhines, PhD students in materials science and engineering. The previous year, a former colleague from Maruska, Jacques Pankive, together with Ed Miller, at the Radio Corporation of America, obtained for the first time blue electroluminescence through gallium nitride but with zinc doping: from it, then, they obtained the first gallium nitride diode to emit green light. In 1974, Maruska, Rhines and Professor David Stevenson received the patent for their invention. In the 1970s, no practical use could be found for gallium nitride diodes doped with magnesium, and research slowed down, only to return decades later with the development of blue LEDs and laser diodes.

In August 1989, Cree was the first company to market blue silicon carbide LEDs, so with an indirect prohibited band that makes the device very inefficient. Also in the late 1980s, key milestones in the epitaxial growth of gallium nitride with doping of acceptors brought optoelectronic devices into the modern era. On this basis, in 1991 Theodore Moustakas, of Boston University, devised a method for the production of high luminescence blue LEDs through a two-step process, obtaining a patent six years later.

In 1993, with a growth process similar to that of Moustakas, Shuji Nakamura, from Nichia, also produced a high luminescence blue LED. Both Moustakas and Nakamura received a patent and this generated confusion as to who was the real inventor of the blue gallium nitride LED, in fact Moustakas discovered his method first but his registration at the patent office was later than Nakamura’s one. The possibility of producing blue LEDs on an industrial scale opened up the development of new technologies and applications in the following decades, so much so that Nakamura received the Millennium Technology Award in 2006 and in 2014, together with Hiroshi Amano and Isamu Akasaki, the Nobel Prize for physics.

In parallel, in Nagoya, Isamu Akasaki and Hiroshi Amano himself worked on the development of a method to grow gallium nitride on a sapphire substrate, doped with acceptors, and on demonstrating the increased efficiency of LEDs made with this process. In 1995, at the University of Cardiff, Alberto Barbieri studied the efficiency and reliability of high luminescence LEDs with a structure formed by layers of aluminum phosphide, gallium and indium (AlGaInP) and gallium arsenide (GaAs), with a “transparent contact” that is a transparent film of indium tin oxide (also known as ITO, Indium tin oxide).

Between 2001 and 2002, methods of growth of gallium nitride on silicon were successfully demonstrated and, in January 2012, Osram found a way to produce industrial quantity LEDs in indium gallium nitride (InGaN) grown on silicon substrates. At least until 2017, manufacturers used silicon carbide substrates, although the most common one remained sapphire because it has properties very similar to gallium nitride, which reduces the formation of defects in its crystalline structure during growth.

At the end of the decade, Samsung and the University of Cambridge carried out research on gallium nitride LEDs grown on silicon substrate, initially followed by Toshiba, but then stopped the research. Some opted for epitaxial growth by nano-printing lithography, while others opted for multi-layer growth to reduce the differences between crystalline structures and thermal expansion rate, in an attempt to avoid chip breakage at high temperatures, decrease heat emission and increase light efficiency.

White LEDs and use in lighting

White light can be produced by using different colored LEDs together: one red, one green and one blue; however, the color quality will be low because only three narrow bands of the visible spectrum are used. A better method is to use a high efficiency blue LED, using the properties of phosphor to produce white light. In these devices, when the blue LED light hits an overlying layer of phosphor, doped with yttrium garnet, aluminum (YAG) and cerium (Y3Al5O12:Ce), it produces a yellow fluorescent light: the overall effect of blue and yellow light has a very wide bandwidth and is therefore perceived as white light by the human eye, with a higher color rendering index than white obtained by combining red, green and blue LEDs.

As with its predecessors, the first white LED was expensive and inefficient. However, the improvement in light output grew exponentially: the latest developments and research have been carried out by Japanese, Korean and Chinese companies, such as Panasonic, Nichia, Samsung and Kingsun. The trend of this growth is defined by Haitz’s Law (pictured), which takes its name from Roland Haitz.

The light emission and efficiency of blue-violet LEDs grew and at the same time the cost of the devices fell, allowing to produce white LEDs with relatively high power, potentially suitable to replace traditional lighting.

In the decade of the two thousand, experimental white LEDs produced 303 lumens per watt of electrical current input, with a life span of up to one hundred thousand hours, although those on the market stopped at 223 lumens per watt. Compared to an incandescent lamp, it was therefore obtained a substantial increase in electrical efficiency at the same price and, sometimes, at an even lower cost.