Smartphones, TVs, computers, iPads, and many
other modern miracles are made possible by power-efficient LED screens. But the real impact goes well beyond our brightly
lit gadgets. Lighting accounts for 20-30% of global electricity
consumption and about 6% of greenhouse gas emissions. Given that LED bulbs use around 80% less energy,
and last 25 times longer than incandescent lighting, they have the greatest potential
impact on energy savings globally. But when the first LEDs were introduced in
the 1960s, they didn’t have much use. It wasn’t until the ‘90s, when Japanese
scientists discovered the missing link needed to complete the color spectrum: the blue LED. Here’s how the color blue changed lighting. After Thomas Edison invented the light bulb
in 1879, incandescent lights lit much of the 20th century. The problem is they waste a lot of energy,
lost in the form of heat, and they don’t last long. Fluorescent lights started being used in the
1930s. Although much more efficient than incandescent,
they’re not an ideal replacement. They contain toxic mercury, age significantly
if they’re frequently switched on and off, and are prone to flicker. There needed to be a better solution. In 1961, Gary Pittman and James R. Biard of
Texas Instruments accidentally invented the first practical light emitting diode while
trying to make a laser diode. The first LEDs emitted infrared light, invisible
to the human eye which later became useful in things like remote controls. And for the next three decades, advances were
made to include red and green, but they couldn’t quite get to blue - which was needed to make
white light. But the appeal was obvious: Unlike ordinary
incandescent bulbs, LEDs don’t have a filament that will burn out, they don’t get hot,
and they require a lot less energy. So the biggest electronics companies raced
to create a powerful blue LED. But the problem of the missing color plagued
them for nearly 30 years. The key ingredient, a chemical compound called
gallium nitride proved difficult to grow in a lab. Scientists tried and failed, ultimately turning
their attention to other “more promising” semiconductor materials for creating blue
light. But a number of favorable circumstances lead
a scientist from a small chemical company in Japan called Nichia to finally make the
discovery: Firstly, by virtue of having little to no budget,
scientist Shuji Nakamura was forced to create red and infrared LEDs from scratch, using
parts he scavenged and fixed by hand. Most companies in the ‘80s were creating
LED material using commercially available equipment. This experience, which took him around 10
years and featured monthly explosions in the lab, would later prove invaluable when doing
trials for blue LEDs. The second reason was his decision to use
gallium nitride, a material considered a “dead end” by other scientists. But his motivation for using the chemical
compound was personal: getting his Ph.D. According to Nakamura, writing papers on less
promising candidates for blue light would make it much easier for him to get the necessary
papers published for his degree. Again he went back to the lab, not taking
holidays and not varying his daily routine. But this time was different. He convinced Nichia to buy the equipment for
manufacturing LED material. Instead of starting from scratch, he made
small modifications to the commercially available equipment -- his extensive experience building
red and infrared LEDs aided the alterations. Just over a year later, Nakamura made his
first successful growth of gallium nitride. His method, called “two-flow MOCVD”, is
still used to this day. From this, and discoveries of other Japanese
scientists around that time, he was able to produce the first brightly shining blue LED. Nichia is still a leader in the LED industry,
used by Apple and other electronics manufacturers. In 2014 Shuji Nakamura was awarded the Nobel
Prize in physics for his invention, along with two other Japanese scientists who developed
high-quality gallium nitride materials prior to Nakamura’s breakthrough. The small, energy-efficient, and extremely
bright LEDs started a light revolution and are now used in almost every piece of electronics. Without it, much of what we use today wouldn’t
be possible. It also has life-changing implications in
the developing world: With LEDs, solar panels and small batteries are more than enough to
power the homes of the 1.2 billion people who lack access to electricity. Most of those people are still burning wood
or gas for light which is not only inefficient, it causes pollution. It’s estimated that switching all lighting
to LEDs would reduce annual carbon dioxide emissions by about the same amount as that
produced by three-quarters of the cars in the U.S. That’s a potentially bigger impact than
wind or solar power. And with global warming due to human activity
generating catastrophic effects on the planet, the desire for saving energy is bigger than
ever.
