At a concert last night, I met up with someone I had not seen for more than 30 years. Ching Tang was the inventor of OLEDs while at the Eastman Kodak research Labs, where I also worked in the 1980s. At that time this brilliant scientist was looking for applications for OLEDs and we were designing blood analyzers that used LEDs as reflectometer light sources. But at that time OLEDs were not very bright and had lifetime issues. But they did have the blue wavelength we were seeking!
Hong Kong-born American physical chemist Ching W. Tang and his co-worker Steven Van Slyke built the first, revolutionary practical OLED device at Eastman Kodak in 1987. It used a novel two-layer structure with separate hole transporting and electron transporting layers such that recombination and light emission occurred in the middle of the organic layer; this resulted in a reduction in operating voltage and improvements in efficiency.
OLEDs have come so far since those days - and he commented how amazing it was to have his invention everywhere - on his cellphone, on a 77" TV in his office in Hong Kong.