US researchers have found evidence suggesting that Thomas Edison may have accidentally created graphene while developing the first light bulb in 1879, more than a century before it was formally identified.

The research, led by Dr. James Tour, professor of chemistry, materials science, and nanoengineering at Rice University, aimed to reconstruct Edison’s original light bulb experiment using modern analytical tools.

Tour’s team recreated the American inventor’s carbon filament light bulb design and applied electrical conditions similar to those used in the 19th century. They then noticed that some of the filaments had transformed into turbostratic graphene.

Turbostratic graphene is a type of multilayer graphene that is stacked with randomly rotated and misaligned layers. It is highly valued for its scalable mass production, especially in energy storage and composite reinforcement.

“Replicating what Thomas Edison did using the tools and knowledge we now have is very exciting,” said Toole, the paper’s corresponding author.

Recreate Edison’s light bulb

Graphene is a two-dimensional sheet of single-atom-thick carbon atoms arranged in a hexagonal honeycomb lattice. Considered the world’s thinnest and strongest material (approximately 200x) stronger than steel), it also ranks among the most conductive materials.

In addition, it is flexible and transparent, acting as an effective barrier against gases and liquids. called “Miracle material” It was first isolated in 2004 by Andre Geim and Konstantin Novoselov at the University of Manchester, UK.

Since its discovery, graphene has become an important material in the electronics and electronics fields. energy storage. Currently, one method of producing turbostratic graphene is known as “flash Joule heating.”

During this process, the current heats up rapidly. carbon-based materials It can withstand temperatures of approximately 3,600 to 5,400 degrees Fahrenheit (2,000 to 3,000 degrees Celsius).

But in the late 19th century, Edison relied on carbon-based filaments, which were often made from natural materials such as Japanese bamboo, rather than the tungsten used in modern incandescent light bulbs.

When electricity flows through these filaments, their electrical resistance causes them to rapidly heat up and produce light. The researchers believe these conditions closely reflect modern flash Joule heating and may have been sufficient to produce graphene.

Discovery of carbon filament

When Lucas Eddy, a Rice University alumnus and lead author of the paper, was trying to find the simplest equipment to mass-produce graphene, he remembered that early light bulbs often used carbon-based filaments.

“I was developing a way to mass-produce graphene using readily available and affordable materials,” Eddy said. “I was looking at everything from an arc welder that was more efficient than anything I had ever built to a tree that had been struck by lightning that was a complete dead end,” he continued.

To test this hypothesis, the researchers sourced artisan-made, Edison-style light bulbs from a small art store in New York City. Original patent from 1879.

The researchers then connected the bulbs to a 110 volt (V) DC power source based on their original settings and powered them for about 20 seconds. They noted that longer exposure times could lead to the formation of graphite.

After the test, scientists Using an optical microscope, we found that the surface of the filament changed from a dark gray color to a silvery, metallic appearance. They then used Raman spectroscopy, a laser-based analytical technique that identifies materials by analyzing their atomic-level features.

As a result, it was confirmed that turbostratic graphene existed in part of the filament. Although there is no way to determine whether graphene survived Edison’s original experiments, the new discovery suggests that it may have formed briefly long before it was discovered.

“The discovery that he may have been able to produce graphene raises curiosity about what other information is buried in this historic experiment,” Tour concluded. press release. The research is published in diary ACS Nano.