Televisions have found an unexpected ally just when their consumption is under suspicion: nanocrystals

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Nanocrystals broke into the television market in 2015. They did it in a big way and with a promise: to drastically expand color coverage that LCD panel televisions delivered to us at that time. And they kept their word. In fact, today they are not only present on these televisions; they are also a fundamental component of the QD-OLED matrices made by Samsung.

At the end of last September, the European Union approved a new directive that seeks to reduce the consumption of televisions, a measure that will possibly cause manufacturers to limit their maximum brightness delivery capacity. Otherwise they will not be able to comply with it, so a priori it is likely that the image modes designed to reproduce HDR content are the main victims.

You may be wondering what this has to do with the nanocrystals we talked about in the first paragraph of this article. It is a fair question, and the good news is that it has a lot to do with it because a research group from the University of Tokyo has developed a new type of nanocrystals that makes it possible to manufacture more efficient televisions and monitors from an energetic point of view. It’s just what we need right now.

The nanocrystals do not condition only the color; also involved in consumption

Before going any further, it is worth stopping for a moment to briefly review what nanocrystals are, also known as quantum dots (in English, quantum dots), and why they are so important. These are tiny crystals of semiconductor material that have a surprising property: they modify the wavelength of the light that interacts with them.

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Curiously, these crystals are so small that their behavior is described by the laws of quantum mechanics, so that it could not be explained using classical mechanics. Their electronic characteristics are defined, on the one hand, by their size, and, on the other, by their shape, which explains why nanocrystals are currently being used for very different applications, such as photovoltaic technology, biological labeling or removal of polluting agents. And, of course, in electronics.

Nanocrystals modify the wavelength of light that interacts with them. In addition, they are immune to humidity and oxidation.

Their ability to modify the wavelength of light is precisely the property that allows them to reproduce a very respectable portion of the visible spectrum. However, this is not its only amazing feature. They’re also impervious to moisture and oxidation, and as a bonus, they can be deposited on a flexible substrate without issue, making them ideal for roll-up displays. In addition, it is cheaper to produce a matrix of nanocrystals than an OLED panel, although, as we have seen, QD-OLED matrices combine both technologies.

The nanocrystals used in televisions are manufactured using cadmium and selenium, and in order to use them it is necessary to deposit them between a layer of organic material and another layer of electron transport, as if it were a sandwich. In any case, what really matters is that, unlike traditional white LED lighting, the light of which must first be filtered to correct the deviation from pure white, and then “tinted” to obtain the colors red, green and blue, the technology of quantum dots uses blue diodes, which produce pure blue light.

Precisely what the Japanese scientists mentioned a few paragraphs above have achieved is to develop a new procedure for manufacturing blue nanocrystals that is more efficient and cheaper. However, these are not its only attractive qualities. According to Eiichi Nakamurawho is the professor at the University of Tokyo who has led this project, when exposed to ultraviolet light, their quantum dots generate blue light of extraordinary purity, which, according to his measurements, fits the demanding standard like a glove BT.2020 used to evaluate the color reproduction of televisions.

In this statement Nakamura clearly describes how are nanocrystals different that has developed its team of employees for seven years on the televisions that many of us have at home:

Until now, to manufacture blue quantum dots it is necessary to resort to relatively large chemical substances that must be subjected to a set of refining processes so that they acquire the appropriate properties. Our strategy is very different. Our team uses chemical elements that have the ability to self-organize in order to precisely control the molecules until they acquire the structure we are looking for.

Somehow what we are doing is building a house brick by brick instead of digging it directly into the rock. Using our strategy it is much easier to be precise and design exactly the structures we are looking for. In addition, this procedure is more efficient and economical.

Sounds really good. Unlike conventional quantum dots, which, as we have seen, are usually made up of cadmium and selenium, the nanocrystals that Nakamura’s team is working with are made up of a mixture of organic and inorganic ingredients. One of them is perovskites, which are a family of materials with a crystalline structure similar to that of calcium titanate of enormous interest in photovoltaic technologies.

In addition, according to these researchers, the structure of their blue quantum dots allows them to carry out their mission more efficiently. This is precisely its most relevant quality at a time when it is crucial to reduce the energy consumption of televisions. This property is linked to a real feat by Nakamura and his team: they have managed to produce nanocrystals as small as 2.4 nanometers. And this means that they are 190 times smaller than the wavelength of the light with which they interact. It’s amazing.

More information: University of Tokyo

Nanocrystals broke into the television market in 2015. They did it in a big way and with a promise: to…

Nanocrystals broke into the television market in 2015. They did it in a big way and with a promise: to…

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