Архив метки: Nanomaterials

Ученые научились создавать углеродные нанотрубки с равномерным покрытием оксида цинка

Исследователи из Сколтеха, Университета Аалто и Санкт-Петербургского Политехнического Университета успешно продемонстрировали технологию осаждения оксида цинка на поверхность пленок однослойных углеродных нанотрубок. Результаты сотрудничества этих исследовательских университетов были опубликованы в журнале Nanotechnology.

Однослойные углеродные нанотрубки (ОУНТ) — это цилиндрические структуры (диаметром несколько нанометров и длиной несколько микрон), состоящие из атомов углерода. ОУНТ обладают уникальными механическими, электрическими и оптическими свойствами, что сделало их одним из наиболее исследуемых в мире материалов. Возможные применения ОУНТ включают композитные материалы, суперконденсаторы, био- и химические сенсоры, транзисторные структуры.

Применение ОУНТ, не подвергшихся модификации, в некоторых областях ограничено, поэтому ученые активно ведут исследования возможностей изменения и улучшения свойств ОУНТ. В данной работе ученые применяли метод обработки ОУНТ азотом, разработанный ранее в лаборатории Наноматериалов Сколтеха, а далее напыляли оксид цинка на поверхность углеродных нанотрубок.

В результате реализации совместного проекта с помощью технологии осаждения атомных слоев (ALD), ученые добились получения равномерного слоя оксида цинка (ZnO) на поверхности однослойных углеродных нанотрубок (ОУНТ) после их обработки в контролируемой атмосфере озона. Снимки просвечивающей электронной микроскопии (ПЭМ) образцов ОУНТ после обработки представлены на Рис. 1а, б. Как видно из Рис. 1а, осаждение ZnO было неэффективным, ZnO не осаждался равномерно на поверхности нанотрубок, а образовывал крупные скопления частиц различной формы. Напротив, на Рис. 1б показан образец с покрытием ZnO, который находился в атмосфере озона в течение 30 мин, до того, как он был перемещен в ALD камеру. Равномерность ZnO покрытия в этом случае отчетливо видна из ПЕМ изображения.

 

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Рис. 1. а – ПЭМ-изображения образцов ОУНТ после 150 циклов ALD без озонирования,б – ОУНТ после озонирования и покрытия ZnO.

 

Последующая обработка нанотрубок, покрытых оксидом цинка, ультрафиолетом позволило добиться их гидрофильности (Рис. 2а и 2б). Гидрофобность нанотрубок затрудняет и использование в растворах, используемых, например, в медицине и фармакологии, а их функционализация – превращение в гидрофильные – позволяет управлять их растворимостью в жидкостях.

Кроме того, использование тонких пленов ОУНТ с ZnO покрытием позволили исследователям получить из полевых транзисторов р-типа (носителем заряда “дырки”) амбиполярные транзисторы (носители заряда “дырки” и электроны). Дело в том, что полевые транзисторы на основе ОУНТ являются транзисторами р-типа в обычных условиях окружающей среды (Рис. 2в), а с помощью напыления оксида цинка ученым удалось изменить их свойства. “Здесь мы объединили ОУНТ, обработанные озоном, и материал ZnO для изменения электрических свойств транзисторного устройства” – поясняет Альберт Насибулин один из соавторов, профессор Сколковского Института Науки и Технологий. “В отличие от транзисторов р-типа, полученных в условиях окружающей среды, наши транзисторы, основанные на ALD покрытии ОУНТ имеют высокую степень амбиполярности более 90% (Рис. 2г). Такое уникальное амбиполярное поведение может стать серьезным внедрением для технологии изготовления полупроводниковых приборов, в которой только один тип носителей заряда является доминирующим при работе устройства. Именно по этой причине, продемонстрированные нами амбиполярные ОУНТ транзисторы, могут быть использованы для изготовления новых логических схем, а также элементов памяти”, – продолжил Альберт Насибулин.

Исследовательская группа Альберта Насибулина активно занимается разработкой новых наноматериалов и их усовершенствованием. Среди последних достижений: разработка метода обработки углеродных нанотрубок озоном, получение нового гибридного материала для использования в сенсорных дисплеях, технологию создания диодов на основе ОУНТ, а также создание эластичных суперконденсаторов на основе ОУНТ.

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Рис. 2. Изменение характера поведения пленки (а) гидрофобная до УФ обработки (б) гидрофильная после УФ-бработки. Вольт-амперные характеристики транзистора на основе ОУНТ в логарифмическом масштабе: в – до ZnO ​​ покрытия, г – после 50 циклов ALD.

Результаты работы опубликованы в журнале Nanotechnology.

Контакты:
Skoltech Communications
+7 (495) 280 14 81

Skoltech presented for the first time at the biggest international conference for the printed electronics industry

Skoltech professor Albert Nasibulin and Ph.D. student Evgenia Gilshteyn from Skoltech’s Laboratory of Nanomaterials took part at the LOPEC conference in Munich, which is the biggest international exhibition and conference for the printed electronics industry. In the event they presented novel results in wearable, printable and stretchable electronics with their poster talk.

Nasibulin and Gilshteyn presented their poster as part of the scientific conference, which is the forum where scientists can discuss the latest concepts and results of their research. We asked Gilshteyn to tell about the presentation and the event. “The topic of our poster was “stretchable electronic devices based on carbon nanotubes”, and the discussion around our poster was quit massive. On the other hand – this conference was a great opportunity to find some new collaborations – with Germany, Israel, Belgium and others, in order to make some joint researches. In addition, it was very interesting to visit the technical conference, which was geared towards industry and applications, as well as promoting the ongoing development of products and business sectors”.

With roughly 200 presentations from about 30 different countries, the LOPEC conference is the world’s leading communication platform for research, knowledge, and solutions in the emerging field of printed electronics industry. This year the conference focused specifically on the challenges that arise when technologies are transformed into marketable applications. The discussions focused on the following sectors: wearables trend, automotive industry and consumer electronics.

Nasibulin and Gilshteyn were the only representative from Russia in the whole event. We hope to see greater Skoltech and Russian presence in future conferences related to this blooming technological area.

Контакты:
Skoltech Communications
+7 (495) 280 14 81

Seminar: Design of Novel Materials For Organic and Hybrid Solar Cells

Solar cells facade on a municipal building located in Madrid, Spain. Image courtesy of Wikipedia, CC

Solar cells facade on a municipal building located in Madrid, Spain. Image courtesy of Wikipedia, CC

We would like to invite you to a guest seminar by Dr. Pavel A. Troshin on the “Design of Novel Materials For Organic and Hybrid Solar Cells”.

When: March 25, 2015, 13.30 – 15.00

Where: Beijing-1 Auditorium, China cluster, Skolkovo School of Management

SEMINAR ABSTRACT:

Organic and hybrid solar cells represent a promising photovoltaic technology which is aimed to deliver cheap electrical energy utilizing inexpensive and abundant materials and high throughput roll-to-roll production technologies. Organic (hybrid) solar cells can be mechanically flexible, light-weight, semitransparent and environmentally friendly.

Rather unique properties of these devices open a number of exciting opportunities for their use in mobile applications, smart windows, textile-integrated photovoltaics (power suits) and etc. Dr. Troshin and his team have contributed significantly to design of novel fullerene-based and polymer-based nanomaterials for organic and hybrid perovskite solar cells demonstrating light conversion efficiencies of 6-11% and improved operation stabilities. Fundamental correlations have been revealed between the molecular structures of the novel materials, their physical and electronic properties and the device performances. The developed approaches can be applied in the future for designing electrode materials for organic batteries.

Dr. Pavel A. Troshin

Dr. Pavel A. Troshin

SPEAKER INTRODUCTION:

Dr. Pavel A. Troshin was born in Bryansky region, Russian Federation. He received his BS and MS degrees in organic and physical chemistry in 2003 from Higher Chemical College of the Russian Academy of Sciences at D. I. Mendeleev University of Chemical Technology of Russia. He obtained his PhD degree in physical chemistry in 2006 from the Institute for Problems of Chemical Physics of the Russian Academy of Sciences (IPCP RAS). He is currently a head of the Research Group for Multifunctional Materials and Organic Electronics at IPCP RAS. His current research focuses on polymer and fullerene chemistry, organic electronics, solar energy conversion, organic batteries and biomedical applications of fullerenes.

Контакты:
Skoltech Communications
+7 (495) 280 14 81

A Match Made in a Reactor: Skoltech and Aalto Researchers Collaborate on Carbon Nanomaterials

Skoltech student Andrey Vyatskikh (front) examines a carbon nanotube sample he has just treated in various solutions and then "fished" out so it can be dried and examined

Skoltech student Andrey Vyatskikh (front) examines a carbon nanotube sample he has just treated in various solutions and then “fished” out so it can be dried and examined

Smartphones with curved screens, super stretchable speakers, and keyboards that can be folded and rolled to a tiny film.

These might all seem futuristic, but such innovative products might soon be available on the market, thanks to nano materials research performed at Skoltech in Moscow and Aalto University in Finland by joint teams of scientists.

For that purpose, Skoltech Energy and Advanced Manufacturing graduate students spent a weekend at Aalto University for a hands-on carbon nanotubes lab, led by professors Albert Nasibulin (Skoltech) and Esko Kauppinen (Aalto U), and TA Evgenia Gilshtein  .

The visitors worked along with Finnish colleagues and local instructors to gain hands-on experience of the technologies and methods used to operate a unique gas-phase reactor, synthesize highly conductive nano-carbon tubes utilizing graphene, and test the materials’ characteristics, for example its ability to stretch and fold much more than materials currently used by electronics companies.

The teams then analyzed the results using tools such as electron microscopes and spectrometers. The lab experience is a first step in a long process, as researchers intend to conduct numerous  experiments over the next year or two – until they can produce stretchable and flexible electronics that can be commercialized.

Professor Albert Nasibulin examines a carbon nanotube reactor at the lab he had helped set up at Helsinki University of Technology (nowadays Aalto University) in the early 2000s. Recently, he has moved to Moscow where he leads nanomaterial research and teaches at Skoltech.

Professor Albert Nasibulin examines a carbon nanotube reactor at the lab he had helped set up at Helsinki University of Technology (nowadays Aalto University) in the early 2000s. Recently, he has moved to Moscow where he leads nanomaterial research and teaches at Skoltech.

The state of the art facility in Finland had been established by Prof Albert Nasibulin in 2000, who later moved to Moscow and now teaches and conducts research at Skoltech. Nasibulin said: “What is being done here is potentially revolutionary.  The next big phase is to enhance the process of carbon nanotube synthesis so that the end result is more conductive and flexible than anything available now.  We are aiming at combining carbon nanotubes and graphene”, he pauses, “like husband and wife”.

This match made in a reactor is the end goal of teams from both universities.

The masters and PhD students also visited the production plant of Canatu, a spin off company established by Nasibulin and three other partners from Aalto a decade ago.

The start-up, which raised 22 million $USD in three rounds of funding, focuses on transparent conductive and programmable films for new applications from car dashboards to tablet screens. Dr David Brown, a shareholder and Canatu’s CTO, presented the company’s development plans and commercialization prospects.

Researchers from Skoltech and Aalto plan to continue the collaboration in the near future and on a long term basis.
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Контакты:
Skoltech Communications
+7 (495) 280 14 81

Seminar: Nanomaterials For Industrial Applications: Theory Contributions To Heterogeneous Catalysis, Gas Separation And Storage

Nanomaterials are increasingly used by various industries. Image courtesy of Brookhaven National Laboratory

Nanomaterials are increasingly used by various industries. Image courtesy of Brookhaven National Laboratory

How can researchers support industry by designing new nanometer-sized materials with outstanding features?

Join us as we host Dr. Andreas Hauser for a seminar titled “Nanomaterials For Industrial Applications: Theory Contributions To Heterogeneous Catalysis, Gas Separation And Storage”

When: November 20, 2014; 13.30 – 15.00

Where: Russian Quantum Center Auditorium, Ural building (-1 floor), Moscow School of Management

SEMINAR ABSTRACT

The properties of molecular structures in the nanometer range and below vary significantly with system size. Though difficult to predict and far from the asymptotic bulk properties, these fluctuations leave a lot of freedom for the design of novel materials with outstanding features.

This talk focuses on the application of electronic structure theory to a selection of topical problems such as membranes for chiral resolution of drug molecules or the separation and storage of gases, and the usage of subnanometer-sized metal particles for heterogeneous catalysis.

Special focus is given to bimetallic alloys for the dehydrogenation of “light end alkanes”, which could open a potential pathway to efficient alkane metathesis and oligomerization reactions.

Their relevance in the context of renewable energies as well as petroleum industries is discussed. Potential projects and their embedding into teaching concepts are suggested to stimulate an open discussion.

Dr. Andreas Hauser, guest speaker at the Skoltech seminar

Dr. Andreas Hauser, guest speaker at the Skoltech seminar

SPEAKER INTRODUCTION

Dr. Andreas Hauser is a physicist working in the field of theoretical chemistry and was recently employed at UC Berkeley as a joint postdoc in the groups of Prof. Martin Head-Gordon (Theoretical Chemistry) and Prof. Alex T. Bell (Biomolecular and Chemical Engineering).

During his stay he participated in the XC2 initiative, a research project of British Petrol on Light Ends Upgrading, Fischer-Tropsch Synthesis, Biomass Deoxygenation and Oxygenate Coupling.

Previous postdoctoral research in the group of Prof. Peter Schwerdtfeger was concerned with the application of nanoporous membranes to various problems of gas separation and storage.

Контакты:
Skoltech Communications
+7 (495) 280 14 81

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