Rice University researchers conducting experiments with virtually identical replicas of the light bulbs designed by Thomas Edison have determined that the 19th-century inventor may have created graphene more than 130 years before scientists confirmed the two-dimensional material’s existence.
The team behind the study suggests that confirming Edison’s role in creating graphene nearly a century and a half ago could motivate a new analysis of other historical scientific experiments to identify additional discoveries that may have been lost to history. The findings may also ask new questions that could be answered by reevaluating their work with modern tools and techniques.
How Edison May Have Created 21st Century Magic Material Graphene
When P.R. Wallace first proposed the concept of a two-dimensional lattice of carbon atoms attached at the sides called graphene, Thomas Edison had already been deceased for nearly two decades. The material’s existence wasn’t scientifically confirmed for several more decades, when Konstantin Novoselov and Andre Geim won the 2010 Nobel Prize in physics for its discovery and description.
Since that event, scientists have continued to explore graphene’s unusual properties, including superconductivity achieved through twisting graphene to a “magic angle.” The transparent material is also extremely strong, leading to several new applications every year.
While scientists have discovered several different methods for creating graphene, the new study analyzes turbostatic graphene. According to the Rice University researchers, this type of graphene can be produced by applying a voltage across a resistant carbon-based material, which rapidly heats it to 2,000-3,000 degrees Celsius. Engineers refer to this process as flash Joule heating.
Although he almost surely did not know it, the researchers suggest that Edison’s original light bulb designs may have created graphene via flash Joule heating. That’s because Edison’s designs did not use tungsten filaments like modern incandescent light bulbs. Instead, the inventor used carbon-resistant filaments, such as Japanese bamboo.
Lucas Eddy, first author on the paper detailing the research and a former Rice graduate, said he was exploring different methods for creating graphene with “readily available and affordable materials” when he came across Edison’s potential accident.
“I was looking at everything from arc welders, which were more efficient than anything I’d ever built, to lightning-struck trees, which were complete dead ends,” the researcher explained. “I was trying to figure out the smallest, easiest piece of equipment you could use for flash Joule heating, and I remembered that early light bulbs often used carbon-based filaments.”
After studying Edison’s work more closely, Eddy determined the famed inventor’s light bulbs likely reached and exceeded the 2,000-degree threshold needed to create graphene. Still, he couldn’t know for sure without performing new experiments with Edison’s designs.
Experiments with Identical Light Bulb Replicas Return “Exciting” Results
According to a statement detailing the study, the Rice researcher’s first attempts to find an actual Edison-style light bulb were unsuccessful. Unlike the 19th-century designs that used bamboo or other carbon-based filaments, all the options Eddy tracked down were made of tungsten.
“You can’t fool a chemist,” he explained.
Fortunately, the search ultimately led to a small art store in New York City that claimed to sell actual artisan Edison-style bulbs. After a quick examination, Eddy confirmed that the bulbs were perfect replicas, including the bamboo filaments, which were only 5 micrometers larger than those in Edison’s early designs.
To test their flash Joule heating theory, the Rice researchers attached the bulb to a 110-volt DC source like those Edison would have used. Next, the team turned the bulb on for 20 seconds before switching it back off. In theory, the bulb’s filament should pass the minimum temperature threshold within that time frame. The team also noted that a longer exposure could result in graphite rather than graphene.
When the researchers examined the filament under an optical microscope, they found that it had changed from its original dark gray to what they termed a “lustrous silver.” Next, the team used Raman spectroscopy to identify the substance via its atomic signature. As hoped, this analysis revealed that a portion of the filament had turned into turbostratic graphene.
‘Edison, in his quest to develop a practical light bulb that could be used in everyday life, may just have produced a substance that is quickly becoming key to the technology-dependent 21st century,” the researchers note.
Discovery Could Inspire Fresh Look at Other Historic Experiments
Although the Rice team’s experiments produced graphene, the researchers conceded that Edison’s experiments didn’t necessarily result in graphene. They also note that even if they could analyze one of the inventor’s original bulbs today, all the graphene would have turned into graphite during Edison’s first 13-hour test.
According to James Tour, the T.T. and W.F. Chao Professor of Chemistry and corresponding author on the paper, successfully reproducing Edison’s tests and producing graphene with modern tools and techniques was “very exciting.” The researcher also noted that their result may prompt several new questions and potential avenues of research focused on other historical experiments.
“Finding that he could have produced graphene inspires curiosity about what other information lies buried in historical experiments,” Professor Tour said. “What questions would our scientific forefathers ask if they could join us in the lab today? What questions can we answer when we revisit their work through a modern lens?”
The study “Evidence for Graphene Formation in Thomas Edison’s 1879 Carbon Filament Experiments” was published in ACS Nano.
Christopher Plain is a Science Fiction and Fantasy novelist and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him directly at christopher@thedebrief.org.