MSU scientists have developed a smart liquid crystals doped quantum dots

MSU scientists have developed a "smart" liquid crystals with the addition of quantum dots — reported Online MSU. The study is published in Advanced Materials. On liquid crystals can be developed with ultraviolet light to record an image, and then read this information — scanning the liquid crystal in the same ultraviolet light and capturing changes in the degree of polarization of the light emitted by the material. Liquid crystals with similar properties are of interest as potential device for recording, storing and reproduction of image information.

"The main idea was to electric or fotoupravlenii parameters fluorescence quantum dots in the LCD matrix" — says Associate Professor, Senior Researcher Department of Chemistry Alexey Bobrovsky, one of the study's authors.

According to the authors, photos and electropilots LCD materials may in the future serve as sources of single photons in quantum cryptography, and can also be used in nanophotonic systems, for example, to create a miniature lasers with low-threshold lasing with photos and features elektronastraivaemymi radiation. 

As reported at MSU:

Liquid crystals … Perhaps one of the few objects of fundamental science, firmly fit into our daily lives. We are in this we see every day, including the screens of mobile phones and laptops. It would seem that there may still be new? However, scientists are constantly complicate the objects of their research to a "new" find and achieve interesting results.

In a recent article published in the journal Advanced Materials (Adv. Mater., 2012, 24, 6216-6222), MSU scientists1 spoke about the remarkable properties of liquid crystals with the addition of quantum dots. "The main idea was to electric or fotoupravlenii parameters fluorescence quantum dots in the LCD matrix" — says Associate Professor, Senior Researcher Department of Chemistry Alexey Bobrovsky, one of the study's authors.

In the obtained materials photocontrollable matrix liquid crystal consists of siloxane oligomers that form a cholesteric phase, the latter is characterized by a helical supramolecular structure, twisted to the left. This matrix was added chiral-photochromic dopant2, having the property of inducing a liquid crystal spiral twist to the right (thus it is slightly podraskruchivaet left helical structure of the LCD). Dopant capable of isomerization under UV light, this leads to weakening of the above-described properties, whereby there twist cholesteric helix.

Due to the unique helical supramolecular organization spiral step comparable to the wavelength of visible light, embedded in the LCD matrix quantum dots were capable of emitting circularly polarized light. After UV irradiation of the material changes its local structure, and thus changing the nature of the radiation from the quantum dots. In other words, the liquid crystal can be UV light to record an image, and then read this information — scanning the liquid crystal in the same UV light and capturing changes in the degree of polarization of the light emitted by the material. Liquid crystals with similar properties are of interest as potential device for recording, storing and reproduction of image information. "Quantum dots are poorly soluble in the liquid crystal matrix," — said Bobrowski possible difficulties along the way — but we are working to radically improve their interoperability. "

Liquid crystal materials are of a somewhat different composition — a compound with a high dielectric anisotropy, stabilized polymers were very sensitive to the application of electric field: it is deformed reversibly blocked helical structure. The degree of polarization of quantum dots in a matrix varies greatly due to the field.

According to the authors, photos and electropilots LCD materials may in the future serve as sources of single photons in quantum cryptography, and can also be used in nanophotonic systems, for example, to create a miniature lasers with low-threshold lasing with photos and features elektronastraivaemymi radiation. To real applications are still far away, but I must say that the very liquid crystals are still about 25 years ago everyone knew only black-and-white screens calculators.

Dr. Ivan Okhapkin,
Management of innovation policy and international scientific relations
1 The article is published in conjunction with researchers from the Institute of Bioorganic Chemistry RAS, Moscow Engineering Physics Institute, Trinity College (Dublin, Ireland) and the Belarusian State universtita (Minsk)
2 Dopant — is, in fact, the addition of

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