We Continue the Work of Those
Who Were the First.

  • Electrical Engineering
  • Light & Lighting
  • Power Engineering
  • Transportation
  • Automation
  • Communication
  • Smart Buildings
  • Industry
  • Innovation

Current issue

ELEKTRO 2/2017 was released on February 17th 2017. Its digital version will be available on March 10th 2017.

 

Topic: Electrical appliances – switching, protective and signalling; Devices for smart grids

 

Main Article

Atypical concept of DC power supply source for high current consumption

SVĚTLO (Light) 1/2017 was released on February 7th 2017. Its digital version will be available on March 7th 2017.

Fair and exhibitions
Invitation on LIGHT IN ARCHITECTURE exhibition 

Architectural and scenic lighting
Lighting design in a nutshell
Spiegeltent illumination and its specificity

Researchers first to create a single-molecule diode

27.05.2015 | PHYS.org | phys.org

Under the direction of Latha Venkataraman, associate professor of applied physics at Columbia Engineering, researchers have designed a new technique to create a single-molecule diode, and, in doing so, they have developed molecular diodes that perform 50 times better than all prior designs. Venkataraman's group is the first to develop a single-molecule diode that may have real-world technological applications for nanoscale devices.

With electronic devices becoming smaller every day, the field of molecular electronics has become ever more critical in solving the problem of further miniaturization, and single molecules represent the limit of miniaturization. The idea of creating a single-molecule diode was suggested by Arieh Aviram and Mark Ratner who theorized in 1974 that a molecule could act as a rectifier, a one-way conductor of electric current. Researchers have since been exploring the charge-transport properties of molecules. They have shown that single-molecules attached to metal electrodes (single-molecule junctions) can be made to act as a variety of circuit elements, including resistors, switches, transistors, and, indeed, diodes. They have learned that it is possible to see quantum mechanical effects, such as interference, manifest in the conductance properties of molecular junctions.

Since a diode acts as an electricity valve, its structure needs to be asymmetric so that electricity flowing in one direction experiences a different environment than electricity flowing in the other direction. In order to develop a single-molecule diode, researchers have simply designed molecules that have asymmetric structures.

Their results achieved rectification ratios as high as 250: 50 times higher than earlier designs. The "on" current flow in their devices can be more than 0.1 microamps, which, Venkataraman notes, is a lot of current to be passing through a single-molecule. And, because this new technique is so easily implemented, it can be applied to all nanoscale devices of all types, including those that are made with graphene electrodes.

Wohle article at Phys.org
Image Credit: Latha Venkataraman, Columbia Engineering