Featured Research

from universities, journals, and other organizations

Touchscreens and solar cells: Simulations for better transparent oxide layers

Date:
September 3, 2014
Source:
Fraunhofer-Gesellschaft
Summary:
Touchscreens and solar cells rely on special oxide layers. However, errors in the layers’ atomic structure impair not only their transparency, but also their conductivity. Using atomic models, researchers have found ways of identifying and removing these errors.

Detail from a model of an amorphous oxide layer into which hydrogen atoms have been introduced in a targeted process. The tiny light-blue sphere on the bottom right is hydrogen; oxygen is represented by small red spheres; the other spheres stand for indium (gray), tin (blue), and gallium (pink).
Credit: © Fraunhofer IWM

Touchscreens and solar cells rely on special oxide layers. However, errors in the layers' atomic structure impair not only their transparency, but also their conductivity. Using atomic models, Fraunhofer researchers have found ways of identifying and removing these errors.

Smartphones, tablet computers, and ticket machines are just some of the many devices nowadays that are touchscreen-operated. These screens are based on special oxide layers that are transparent and conduct electricity. The technical term is TCO (transparent conducting oxide) layers. TCOs are also used on solar cells and in heated windows. So that the technology keeps pace with new products and applications, manufacturers are constantly improving the layers, making them better conductors of electricity and increasing their transparency -- after all, when used in tablet computer or smartphone displays, users need to be able to see the content on the screen clearly through the layers. Any additional sheen caused by the oxide would be a problem. The same principle applies for solar cells: rather than impeding sunlight, the oxide layers must allow it to pass unobstructed into the cell. Accordingly, transparency and conductivity are the key elements that the developers of new oxide layers must consider -- but the manufacturing temperature and the plasticity of the layers are also important.

Realistic simulation of atomic structure

Researchers at the Fraunhofer Institute for Mechanics of Materials IWM in Freiburg help manufacturers to optimize oxide layers. "We've developed a practical and effective method for simulating the properties of TCO layers," says IWM scientist Dr. Wolfgang Körner. Most impressive of all is the fact that the scientists' simulations of the layers' atomic structure are highly realistic and take into account all possible atomic errors -- irrespective of whether the layers are disordered, amorphous structures or crystalline, highly ordered ones. On the basis of these simulations, the scientists then investigate how well the electrons can move in the layer, in other words how well the oxide conducts electrical current.

"We can specifically track how a layer's density of states changes when we change its atomic structure," explains Körner. The researchers can also establish whether light is absorbed or passes through the layer unobstructed, making it appear transparent. "Because we do the trial-and-error material tests on a computer, we can calculate the properties possessed by the respective material composition of the TCO being studied much faster and more cost-effectively than by traditional means," says Körner. Through his projects, Körner is deepening our understanding of how the different properties of the oxide layers arise. This understanding is helping his industrial partners to improve their production and to obtain specific oxide layer properties.

The researchers have already managed to find the principal defects that occur in these layers. It is simply not possible to manufacture the structures with absolutely zero errors. As much as manufacturers want them to consist only of certain defined atoms such as zinc, tin, and oxygen, other atoms -- hydrogen is a common culprit -- have a habit of crashing the party, changing the layer's conductivity and transparency. But what defects in atomic structure actually impair transparency? And how can we remove these defects to make the oxides more transparent? One of the researchers' findings was that the transparency of certain oxides is improved by heating them once to a suitably high temperature or by heating them up in an oxygen-rich environment.

A second approach sees the scientists tackle the problem from the other end: they add various specifically defined atoms into the structure and simulate the effects this has on a layer's properties. The goal here is to further boost conductivity and transparency by means of suitable "impurities" and to be able to design a material by computer in this way.


Story Source:

The above story is based on materials provided by Fraunhofer-Gesellschaft. Note: Materials may be edited for content and length.


Cite This Page:

Fraunhofer-Gesellschaft. "Touchscreens and solar cells: Simulations for better transparent oxide layers." ScienceDaily. ScienceDaily, 3 September 2014. <www.sciencedaily.com/releases/2014/09/140903091734.htm>.
Fraunhofer-Gesellschaft. (2014, September 3). Touchscreens and solar cells: Simulations for better transparent oxide layers. ScienceDaily. Retrieved October 1, 2014 from www.sciencedaily.com/releases/2014/09/140903091734.htm
Fraunhofer-Gesellschaft. "Touchscreens and solar cells: Simulations for better transparent oxide layers." ScienceDaily. www.sciencedaily.com/releases/2014/09/140903091734.htm (accessed October 1, 2014).

Share This



More Matter & Energy News

Wednesday, October 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Japan Looks To Faster Future As Bullet Train Turns 50

Japan Looks To Faster Future As Bullet Train Turns 50

Newsy (Oct. 1, 2014) — Japan's bullet train turns 50 Wednesday. Here's a look at how it's changed over half a century — and the changes it's inspired globally. Video provided by Newsy
Powered by NewsLook.com
US Police Put Body Cameras to the Test

US Police Put Body Cameras to the Test

AFP (Oct. 1, 2014) — Police body cameras are gradually being rolled out across the US, with interest surging after the fatal police shooting in August of an unarmed black teenager. Duration: 02:18 Video provided by AFP
Powered by NewsLook.com
Raw: Japan Celebrates 'bullet Train' Anniversary

Raw: Japan Celebrates 'bullet Train' Anniversary

AP (Oct. 1, 2014) — A ceremony marking 50 years since Japan launched its Shinkansen bullet train was held on Wednesday in Tokyo. The latest model can travel from Tokyo to Osaka, a distance of 319 miles, in two hours and 25 minutes. (Oct. 1) Video provided by AP
Powered by NewsLook.com
Robotic Hair Restoration

Robotic Hair Restoration

Ivanhoe (Oct. 1, 2014) — A new robotic procedure is changing the way we transplant hair. The ARTAS robot leaves no linear scarring and provides more natural results. Video provided by Ivanhoe
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins