Successfully manufactured the smallest organic light emitting device

To help make the nano world brighter, a group of interdisciplinary researchers have produced microscopic "nanoparticles" - light-emitting nanofibers about the size of a virus or a microchip. Smallest bacteria.

In collaboration with experts in organic materials and nanotechnology, the scientists have created one of the smallest organic light-emitting devices ever made of synthetic fibers. The case is only 200 nanometers wide. Potential applications will be applied to flexible electronic products, which are increasingly smaller and smaller.

These fibers are made of a compound based on ruthenium metal elements so small that they are smaller than the wavelength of the light they emit. Such zoned light sources are useful for applications ranging from sensors to microscopes and flat screens.

Close-up illustration of an electrochemical filament.During the experiment, organic devices emitted orange light.(Photo: Cornell University)

This work, published in the March issue of Nano Letters , is a collaboration of 9 Cornell scientists, including the first author José M. Moran-Mirabal - PhD doctoral student. physical application; Mr. Héctor Abruña - Professor of Chemistry and Biochemistry; George Malliaras - associate professor of materials science and technology, Cornell University director of Nanoscale; and Harold Craighead, professor of manufacturing, director of the Nano Biotechnology Center funded by the National Science Foundation.

Using an electrospinning technique , the scientists turned these fibers from a mixture of metal complexes of ruthenium tris-bipyridine and polymer oxide polymer. They discovered that the fibers emit orange light when activated by a low voltage through tiny electrodes - like a tiny light bulb.

'Imagine that you have an extremely small light bulb,' said Malliaras, an expert in organic materials. 'Then you can use this light to illuminate objects that if you don't have this light, you won't see them.'

Craighead's research team has focused on nanostructures and devices and provides expert opinion on electrochemical rotation techniques.

The technique, according to Moran-Mirabal, who works in Craighead's lab, is comparable to pouring syrup on a sandwich on a spinning table. When the syrup is poured in, it forms a spiral pattern on the sandwich, which in the electrochemical rotation technique is the substrate with tiny yellow electrodes. The syrup will become a solution containing a mixture of polymers and complex metals in the solvent. A high voltage between a microscopic peak and a substrate will push the solution from this peak and form a thin liquid beam that is stretched. When the solvent evaporates, the fiber hardens, leaving a solid strand on the substrate.

When scientists find ways to innovate - and shrink - electronics, they are very interested in organic light-emitting devices because they promise the ability to create panels that emit light. light but also flexible, said Moran-Mirabal. 'An application of organic light-emitting devices could be integration into flexible electronic devices,' he said.

Scientists have also demonstrated that these tiny light-emitting devices can be made using simple fabrication methods . Compared with traditional high-resolution lithography methods, which have been etched onto pieces of silicon, the electrochemical rotation technique hardly requires any fabrication and execution. Simpler.

"The durability of organic devices is still being studied, and this newly completed research is no exception ," Craighead said.

'The current concern is the ease of making this material into tiny light-emitting fibers,' he said. 'I think its basic usefulness depends on how well it can withstand subsequent processing and subsequent use.'

Thanh Van