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:10/10/2017)... ... October 10, 2017 , ... ... pharmaceutical company advancing targeted antibody-drug conjugate (ADC) therapeutics, today confirmed licensing rights ... (Hybrid Polymerized Liposomal Nanoparticle), a technology developed in collaboration with Children’s Hospital ...
(Date:10/10/2017)... DALLAS , Oct. 10, 2017 International research firm ... IoT Strategy, will speak at the TMA 2017 Annual Meeting , ... key trends in the residential home security market and how smart safety ... ... "The ...
(Date:10/10/2017)... ... October 10, 2017 , ... The Pittcon Program Committee is ... honoring scientists who have made outstanding contributions to analytical chemistry and applied spectroscopy. ... world’s leading conference and exposition for laboratory science, which will be held February ...
(Date:10/9/2017)... , ... October 09, 2017 , ... At its national ... Christopher Stubbs, a professor in Harvard University’s Departments of Physics and Astronomy, has been ... a member of the winning team for the 2015 Breakthrough Prize in Fundamental physics ...
Breaking Biology Technology:
(Date:4/19/2017)... York , April 19, 2017 ... as its vendor landscape is marked by the presence ... market is however held by five major players - ... Together these companies accounted for nearly 61% of the ... the leading companies in the global military biometrics market ...
(Date:4/13/2017)... India , April 13, 2017 According to ... Proofing, Identity Authentication, Identity Analytics, Identity Administration, and Authorization), Service, Authentication Type, ... MarketsandMarkets™, the IAM Market is expected to grow from USD 14.30 Billion ... Growth Rate (CAGR) of 17.3%. ... MarketsandMarkets ...
(Date:4/11/2017)... NXT-ID, Inc. (NASDAQ:   NXTD ) ("NXT-ID" or ... independent Directors Mr. Robin D. Richards and Mr. ... the company,s corporate governance and expertise. ... Gino Pereira , Chief Executive Officer said," ... and benefiting from their considerable expertise as we move forward ...
Breaking Biology News(10 mins):