While the generally held view is that LED's were invented in the 60's by american researchers, electrophoresis has been known for more than 100 years. In a new twist it emerges that LED's were invented and even patented by a russian genius Oleg Losev in the 1940's ! The irony is that Losev apparently died of starvation in Leningrad during the Nazi invasion of Russia.New Scientist has this to say
If you look in an encyclopaedia, the LED was invented by four independent American research groups in 1962. But the latest edition of Nature photonics reveals that it was actually discovered by a little-known Russian genius around 40 years earlier.
Oleg Vladimirovich Losev was a radio technician with a fierce talent. In the mid 1920s he noticed that diodes used in radio receivers emitted light when current was passed through them. Then, in 1927, he published details in a Russian journal of the first ever LED. Nikolay Zheludev, at the University of Southampton, has dug up Losev's story.
Losev also published on his discoveries in German and British journals. In sixteen papers between 1924 and 1930 he comprehensively detailed the function of his LED. He used Einstein's then new quantum theory to explain the way electrons dropping in energy produced the light without releasing heat. But a letter he wrote to Einstein asking for help developing the theory of LEDs received no reply.
Most significantly, in 1927 Losev filed a patent for a 'light relay' that used his devices 'for fast telegraphic and telephone communication, transmission of images and other applications...' He therefore foreshadowed the development of opto-electronics, which is fundamental to the fibreoptic links that make modern communcations possible.
Impressive stuff. But sadly not work that anyone picked up to take further. And Losev died of hunger in 1942 during the blockade of Leningrad, at the age of 39. In November 1941, he tried in vain to get a paper based on his discovery that "using semiconductors, a three-terminal system may be constructed analogous to a [vacuum] triode” out of Leningrad. It didn't make it. Zheludev asks: "Was it a paper on what we now know as a transistor? We shall never
know for certain unless his manuscript is found."
Zheludev also points out that Henry Round, assistant to radio pioneer Marconi, was the first to discover that semiconductors could produce light, some hundred years ago. He published only a very short note on the matter and made no further investigations. But the piece was never seen by Losev, who must be retrospectively declared the inventor of the LED.