RIA Novosti: Russian scientists develop a substance that can act as a potential component for super-efficient organic light-emitting diodes

Organic Light Emitting Diodes, better known as OLEDs, are the most promising in the electronics industry. They are flexible, thin and have low power consumption. Yet, even they convert only 25% of the consumed electricity into light. The remaining three-quarters turn into heat, thus heating a device.

St Petersburg University researchers synthesised organometallic phosphors based on the so-called acyclic diaminocarbenes. In future, they are expected to increase the efficiency of OLED light emission up to 100%.

The findings of the research supported by a grant from the Russian Science Foundation are published in the scientific journal Dalton Transactions.

In the molecule of the obtained substance, the platinum atom is connected to several organic fragments. Such complexes are well known to scientists due to their photoluminescence, i.e. the ability to glow when irradiated. They are used to make light-emitting polymers, as optical sensors and as photocatalysts.

However, organometallics with acyclic diaminocarbenes were not previously used for the production of light sources, since there was no data on its ability of electroluminescence, i.e. the emission of light when a current is passed. Organometallic phosphors were difficult to obtain. At the intermediate stage of development, transformations could occur with an organic fragment, due to which the result was not the substance that was intended.

The chemists at St Petersburg University used a promising synthesis method to initially form a metal-containing compound. The final modification of the organic fragment occurred directly inside this compound. This ensured the stability of the molecule during the development process and enabled the researchers to obtain a previously inaccessible type of light emitter with improved characteristics.

The synthesised phosphor glows green when a current is passed through it. To conduct experiments, the scientists assembled models of organic light emitting diodes, using the substance as a light-emitting layer. The invention demonstrated high stability. The light remained constant even when the voltage changed, and the device did not overheat during its operation.

Experimental samples showed a brightness 1.5 times higher than that of their closest counterparts. It was also found that if you change the design of the LED, the glow becomes white. As a result, the researchers could use the phosphor in the manufacture of sources of both green and white light.