Navigation Links
Nanoswitches toggled by light
Date:3/5/2008

This release is available in German.

Microscopic fissures in a tiny crystal open and closeon command. Researchers led by Ahmed H. Zewail successfully used ultrafast electron microscopy (UEM) to observe nanoscopic structures at their exercises, as they report in the journal Angewandte Chemie. Such switchable nanochannels could be useful for future nanoelectronics and nanoscopic machines.

Zewail and his team at the California Institute of Technology (Pasadena, USA) are renowned for their work in ultrafast science and technology. Zewail received the Nobel Prize in Chemistry in 1999 for the development of ultrafast laser techniques that are capable of revealing the motions of individual atoms within a molecule during a reaction. The most recent development to spring from Zewails Laboratory is ultrafast electron microscopy. This technique is a combination of a femtosecond optical system (a femtosecond equals 10-15 seconds) with a high-resolution electron microscope; the result is a new tool with extremely high resolution in time as well as in space.

Zewail and his team have now discovered that needle-shaped microcrystals of copper and the organic compound TCNQ (7,7,8,8-tetracyanoquinodimethane, C12H4N4 ), a crystalline, quasi-one-dimensional semiconductor, exhibit optomechanical phenomena that could be of use in nanoelectronic applications. The investigation showed that these crystals stretch out to become longer (but not wider) when they are irradiated with laser pulses in the microscope. If the irradiation is switched off, they contract back to their original size. This effect was most obvious when one of these needles was broken by the shock of a short, strong laser pulse: A small crack of some ten to one hundred nanometers forms at the break. When the crystal is stretched out under irradiation, the nanoscale channel closes up; upon contraction, it reappears. The phenomenon is reversible, as confirmed by UEM.

Why do these micromaterials stretch under light? Within the crystal, the negatively charged TCNQ ions are arranged so that their central, flat, six-membered rings are piled up on top of each other in the long direction of the needle. The energy of a laser pulse excites electrons; part of this energy is transferred, resulting in uncharged TCNQ molecules. For the uncharged TCNQ, the stacked arrangement is no longer favorable, they now require more space and cause the crystal to grow longer. The degree of stretching depends on the strength of the energy absorbed.

Our fundamental in situ UEM observations, which reveal the behavior of nanoscopic matter in space and time, opens up new areas to explore, especially in materials science, nanotechnology, and biology, says Zewail.


'/>"/>

Contact: Ahmed H. Zewail
zewail@caltech.edu
626-395-6536
Wiley-Blackwell
Source:Eurekalert

Related biology technology :

1. Synvista Therapeutics Highlights Newly Published Data Demonstrating the Value of Haptoglobin Genotype Testing In People with Diabetes
2. MEDEA+ Noblanc award highlights improvements in microelectronics
3. National Nanotechnology Initiative releases its fiscal year 2009 budget and highlights
4. Coalition for a Competitive Pharmaceutical Market Launches New Print Ad Campaign Highlighting Need for Meaningful Biogenerics Legislation
5. CyberKnife Users Meeting Highlights Major Clinical Data Milestones and Emerging Trends
6. CellCyte Genetics Corp. Continues to Move Its Technology Forward in Light of Plaintiff Law Firm Press Releases
7. BioTrends Releases Fourth Annual Nephrology TreatmentTrends Publication Highlighting Market Trends for Renal Anemia, Hyperphosphatemia, and Secondary Hyperparathyroidism
8. Oncothyreon highlights corporate and clinical objectives for 2008
9. The Michael J. Fox Foundation Awards $2 Million to Shed Light on Role of LRRK2 and Alpha-Synuclein Genes in Parkinsons Disease
10. CryoCor to Highlight Products at 13th Annual International Boston Atrial Fibrillation Symposium
11. Arpida Receives Green Light From US FDA for Phase II Efficacy Trial With Oral Iclaprim
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:12/7/2016)... 2016 /PRNewswire/ - OncoQuest Inc. ("OncoQuest"), a biopharmaceutical ... immunotherapeutic products for the treatment of cancer, today ... Manufacturing Development Program with Cytovance Biologics ( ... oregovomab antibody product. Supported by recent positive interim ... in ovarian cancer patients, OncoQuest has engaged Cytovance ...
(Date:12/7/2016)... , Dec. 7, 2016  Biocom, the association for the ... statement below following passage of 21 st Century Cures ... November 30 by a 392-26 vote and in the Senate ... be attributed to Joe Panetta , president & CEO ... will give hope to millions of patients around the world. ...
(Date:12/7/2016)...  Genprex, Inc. a biopharmaceutical company focused on ... announced that it has retained ICR Healthcare, a ... and advisory firm, to develop and implement an ... investor relations, public relations and digital communications to ... Genprex and its lead candidate Oncoprex, which is ...
(Date:12/7/2016)... Regen BioPharma Inc. (OTCQB: RGBPP) In a recent ... team of scientists in Guangzhou, China ... of NR2F6 in patients with early cervical cancer correlates with ... cancer tissue as well as in the normal tissue surrounding ... study and the first that I am aware of that ...
Breaking Biology Technology:
(Date:12/7/2016)... 2016 According to a new market research report "Emotion ... Expression, Voice Recognition), Service, Application Area, End User, And Region - Global Forecast ... USD 6.72 Billion in 2016 to USD 36.07 Billion by 2021, at a ... Reading ... MarketsandMarkets Logo ...
(Date:12/6/2016)... Dec. 6, 2016  Zimmer Biomet Holdings, Inc. (NYSE and ... an offering of €500.0 million principal amount of its 1.414% ... of its 2.425% senior unsecured notes due 2026. ... on December 13, 2016, subject to the satisfaction of customary closing ... The Company intends to use ...
(Date:12/2/2016)... , December 1, 2016 ... type (Fingerprint, Voice), Future Technology (Iris Recognition System), ... Region - Global Forecast to 2021", published by ... 442.7 Million in 2016, and is projected to ... a CAGR of 14.06%.      (Logo: ...
Breaking Biology News(10 mins):