Tuesday, February 3, 2015

Novoselov achieved flexibility and transparency – BBC

Hide TV into a tube and carry it home from the store will soon be due to the opening of Nobel Prize winner Konstantin Novoselov, whose team learned how to make flexible and transparent LEDs for a new generation of gadgets.

The team famous physicist Konstantin Novoselov from the University of Manchester, received in 2010 to Andrey Geim Nobel Prize for the discovery of graphene, developed a prototype device, which in the future will be the basis for new translucent, flexible screens and other systems output.

In recent years, research interests Geim and Novoselov slightly parted: Andrew continues to pursue new properties of this material (its membrane qualities he told “Gazeta.ru” in November ), Constantine focused on building new heterostructures with its use. “Once we realized that there is a stable material, graphene, a thickness of only one atom, we realized that he was not alone. There are a class of two-dimensional films, and we pretty quickly switch to them because now the graph takes only a quarter of my work, “- said Novoselov” Gazeta.ru ».

Having the whole” library “of two-dimensional materials, with different properties, from conducting to insulating, from optically active until translucent, scientists decided to put them in a stack, the so-called heterostructures, for the discovery of which Alferov won the Nobel Prize in 2000. Such substances include for example boron nitride, and dichalcogenides. Combining layers in these “cakes”, scientists can obtain physical properties that individually each layer does not have.

In a paper published in the journal Nature Materials , physics told how, specially folded film of boron nitride and molybdenum disulphide titanium sulfide created heterostructure capable of luminescing by passing electric current through it. Graphene itself here assigned fairly modest role: graphene films here are used as transparent electrodes to which current is supplied.

actually get the LED feature is the opportunity to give it in advance the required properties simply by changing the composition of the multilayer heterostructures.

In this case, the emission layer, one of the stacks of 10-40 atomic layers emits light with its entire surface. So far, scientists have been able to get the LEDs emitting in the red and infrared bands.
«varying materials, we can control the frequency of the radiation, as different materials give a different color, and, moreover, we can combine these colors,” – said Novoselov. “Since our new type of LEDs consists of several two-dimensional film thickness of one atom, they are transparent and flexible. Now we are considering a new generation of optoelectronic devices – from transparent to laser illuminators and more complex devices, “- said Fred Uitters, co-author of the work.

According to scientists, one of the advantages of such a heterostructure is that for her superstructure almost no restrictions and a few adjacent layers can encode many functions of all devices:

ten layers obtained LED, five layers – the transistor, and five layers – solar battery, etc.

At the same time the opportunity to bend to such structures allows you to change the frequency or polarization of the emitted light at the fold. Scope of possible applications of the new technology is very wide. Multilayer glowing heterostructure can give impetus to the production of a new generation of mobile phones, tablets and TVs, lighting systems that can simultaneously be thin, light, flexible and durable at the same time.

«The range of possibilities heterostructures will grow as the number of available two-dimensional crystals and improve their quality, “- says Novoselov.

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