Japanese researchers have developed a new material for organic light-emitting diodes (OLEDs) that is free of rare metals, paving the wasy for the development of cheaper OLED displays for smartphones and other devices.

Existing OLEDs use fluorescent and phosphorescent materials. Fluorescent substances are cheap but they have low efficiencies of electroluminescence. Phosphorescent substances have electroluminescence efficiencies of almost 100%, but they require the use of iridium or other expensive rare metals.



A team led by Chihaya Adachi, director of Kyushu University's Center for Organic Photonics and Electronics Research, said they created a a series a of new organic electroluminescent (EL) molecules, carbazolyldicyanobenzene (CDCBs), which do not contain precious metals. The material is as cheap as fluorescent substances and is as efficient (more than 90%) in electroluminescence, or the use of electrons to induce light emission, as phosphorous substances, they said.

The team named the new material's light-emitting features "hyperfluorescence."

Without the use of rare metals, the costs for materials in OLEDs can be reduced to about one-10th, the scientists said.

The team?s research results were published in the Dec. 13 edition of Nature journal.