Tin is finding growing role in new, efficient technologies

Sourced from PeriodicTable.com

Tin is traditionally thought of as a material used in tinplating, solders, glass making and in alloys such as bronze and pewter. However, more recently, tin has established a higher-tech profile through its inclusion in the transparent metal indium tin oxide (ITO), which is often used in touchscreens and on airplane windows. “Traditional” no more…tin is now being used in a number of innovative, advanced technologies.

Indium tin oxide for future light-based electronics

It has been proven that the transfer of information through photons or light particles is very effective and efficient, primarily in terms of speed. To use photons with even greater dexterity, the material’s design needs to control the way light behaves as it passes through the system.

One way to do this is to adjust the material’s refractive index to cause light to travel faster or slower through it. This is particularly achievable for materials that naturally alter their refractive index according to the intensity of light to which they are exposed. Such materials behave differently depending on whether the light passing through comes from a low-power source or a high-powered laser. These materials are known as optically nonlinear. In the world of photonics, having a higher degree of optical nonlinearity is considered an attractive trait.

Research teams at the Universities of Ottawa and Rochester have found that ITO can achieve a particularly high degree of optical nonlinearity — making it a good candidate for photonics applications. The Ottawa/Rochester team’s sample has achieved a degree of nonlinearity that beat that of other materials by factors of 100. For example, the team reports that ITO’s nonlinearity is about 10,000 times larger than carbon disulfide, a popular reference material, and several hundred times larger than gallium arsenide, a compound semiconductor frequently used in light emitting diodes.

As well, some materials snap quickly back to their original refractive index once photons have passed through, while others linger in their new state. For most applications, it’s helpful if a material can make this adjustment faster rather than slower. In the Ottawa/Rochester experiments, ITO recovered in just 360 femtoseconds—a few millionths of a billionth of a second.

You can read more here:

http://spectrum.ieee.org/tech-talk/semiconductors/optoelectronics/indium-tin-oxide-might-be-the-material-photonics-has-been-waiting-for

http://science.sciencemag.org/content/352/6287/795

Tin could enable faster computing and increased storage capacity

In other tin-enabled material developments, scientists at the U.S. Department of Energy’s Ames Laboratory have recently announced the discovery of a new platinum-tin PtSn₄ material that can conduct electrons close to the speed of light. The unique electronic structure of PtSn₄ may someday lead to energy efficient computers with increased processor speeds and data storage. Their work has been published in the journal Nature.

The electrons in materials such as PtSn₄ can travel close to speed of light thanks to a unique property called Dirac dispersion. Up until now, only isolated points, called Dirac points, with relatively small numbers of conduction electrons, were known to exist in such materials. In PtSn₄ specifically, the scientists not only discovered a high density of conduction electrons, but also large number of closely positioned Dirac points forming extended lines or Dirac node arcs.

Tin in ultra-thin solar panels

Also recently, an Australian research team at the University of New South Wales (UNSW) published their work on new ultra-thin solar cells made from CZTS – copper zinc tin sulphide. The UNSW’s Australian Center for Advanced Photovoltaics has achieved a 7.6% efficiency record for a ‘full sized’ CZTS PV cell, the results being confirmed by the National Renewable Energy Laboratory. Their research has shown record energy efficiencies – 50 times thinner than a human hair, however there is still work needed to improve efficiency to commercially viable levels. The UNSW team touts that CZTS will rival leading thin film technologies cadmium telluride (CdTe) and copper indium gallium selenide (CIGS), using relatively abundant materials,within the next few year. As well, CZTS does not carry any deleterious effects of cadmium or selenium.

Similar work globally is making good progress towards theoretical efficiencies of 20% or more. New ultra-thin tin solar cells could lead to ‘zero-energy’ buildings.

Until soon… Ian

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