How Blue LEDs Changed the World

Smartphones, TVs, computers, iPads, and manyother modern miracles are made possible by power-efficient LED screens.

But the real impact goes well beyond our brightlylit gadgets.

Lighting accounts for 20-30% of global electricityconsumption 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 potentialimpact on energy savings globally.

But when the first LEDs were introduced inthe 1960s, they didn’t have much use.

It wasn’t until the ‘90s, when Japanesescientists 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 bulbin 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 the1930s.

Although much more efficient than incandescent, they’re not an ideal replacement.

They contain toxic mercury, age significantlyif 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 ofTexas Instruments accidentally invented the first practical light emitting diode whiletrying to make a laser diode.

The first LEDs emitted infrared light, invisibleto the human eye which later became useful in things like remote controls.

And for the next three decades, advances weremade to include red and green, but they couldn’t quite get to blue – which was needed to makewhite light.

But the appeal was obvious: Unlike ordinaryincandescent 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 racedto create a powerful blue LED.

But the problem of the missing color plaguedthem for nearly 30 years.

The key ingredient, a chemical compound calledgallium nitride proved difficult to grow in a lab.

Scientists tried and failed, ultimately turningtheir attention to other “more promising” semiconductor materials for creating bluelight.

But a number of favorable circumstances leada scientist from a small chemical company in Japan called Nichia to finally make thediscovery: Firstly, by virtue of having little to no budget, scientist Shuji Nakamura was forced to create red and infrared LEDs from scratch, usingparts he scavenged and fixed by hand.

Most companies in the ‘80s were creatingLED material using commercially available equipment.

This experience, which took him around 10years and featured monthly explosions in the lab, would later prove invaluable when doingtrials for blue LEDs.

The second reason was his decision to usegallium nitride, a material considered a “dead end” by other scientists.

But his motivation for using the chemicalcompound was personal: getting his Ph.

D.

According to Nakamura, writing papers on lesspromising candidates for blue light would make it much easier for him to get the necessarypapers published for his degree.

Again he went back to the lab, not takingholidays and not varying his daily routine.

But this time was different.

He convinced Nichia to buy the equipment formanufacturing LED material.

Instead of starting from scratch, he madesmall modifications to the commercially available equipment — his extensive experience buildingred and infrared LEDs aided the alterations.

Just over a year later, Nakamura made hisfirst successful growth of gallium nitride.

His method, called “two-flow MOCVD”, isstill used to this day.

From this, and discoveries of other Japanesescientists 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 NobelPrize in physics for his invention, along with two other Japanese scientists who developedhigh-quality gallium nitride materials prior to Nakamura’s breakthrough.

The small, energy-efficient, and extremelybright LEDs started a light revolution and are now used in almost every piece of electronics.

Without it, much of what we use today wouldn’tbe possible.

It also has life-changing implications inthe developing world: With LEDs, solar panels and small batteries are more than enough topower the homes of the 1.

2 billion people who lack access to electricity.

Most of those people are still burning woodor gas for light which is not only inefficient, it causes pollution.

It’s estimated that switching all lightingto LEDs would reduce annual carbon dioxide emissions by about the same amount as thatproduced by three-quarters of the cars in the U.

S.

That’s a potentially bigger impact thanwind or solar power.

And with global warming due to human activitygenerating catastrophic effects on the planet, the desire for saving energy is bigger thanever.

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