Wuhan "85 after", zhang lei, as the first author Dr Us on December 14, published online in the journal nature materials in the latest research results, a new kind of transparent conductive material, attracts the world attention. The study results can make large screen display, smart Windows, touch screen and solar cells more efficient and cheap, has successfully for the first time since 1977 by shannon, doped semiconductor to design the principle of transparent conductive material, after long-term follow this line of thinking by people for the challenges.
Traditional transparent conducting materials - indium tin oxide, over the past few decades has been dominated, owning more than 90% of the show in market share. Over the past 10 years, however, indium prices rose sharply, a display and a touch screen module is up 40% of mobile equipment's production cost. For a long time, memory and CPU follow Moore's law, is becoming more and more cheap, but smart phones and flat panel display because of size effect, is becoming more and more expensive. Manufacturers have been looking for possible alternative indium tin oxide material, but has not been found to have other materials can be learned in light transparency, conductivity, and easy to manufacture as well. Recently, zhang lei's Pennsylvania state university "engel - Herbert group" has come up with a new material design strategy.
In the new material design, does not use traditional wide bandgap semiconductors, such as indium tin oxide and zinc oxide, but instead USES two kinds of unusual 10 nanometers thick metal film, strontium and calcium vanadate vanadium acid. "The two materials are strongly associated with metal, the electrons in the strong correlation in the metal showed similar to the nature of the" liquid ", in the conventional metal, such as aluminum, copper, gold, silver, electronic mostly showed similar to the nature of the "gas", like a conventional metal show the high reflection and absorption features." In the article, the author explain why strong associated metal while maintaining high conductivity of metal at the same time, optical properties compared with conventional metal has a great improvement.
"By changing the electron effective mass, we make the metal to become more transparent." Penn state university engel, assistant professor of materials science and engineering - Herbert is introduced: they choose the kind of material is greater than the kinetic energy of the interaction between electrons, due to the strong electron correlation effect, electron can "feel" to each other, so that its property is similar to "fluid", not "gas" without interaction. This electronic "liquid" is still conductive, but a reflection of visible light wave band is greatly reduced, so as to improve the transparency. At present, the research team is working with member of the American association for the advancement of science, the rutgers university material theory expert professor karin John rabe, researchers believe they will find a lot of material as vanadate strontium (ca).
New material design strategy is to first recognize and zhang found, is also the first author of the article. Zhang was born in 1985 in wuhan, attended wuhan university, is "engel - Herbert team" doctoral graduate student, before joining the team, he has worked as process integration engineer in silicon valley in the United States for two years.
"Many companies even start-ups, are trying to optimize the indium tin oxide, and looking for potential substitutes. However, after the optimization and improvement on the similar material, improved the space is very limited." Zhang lei, made after the relevant electrical measurement, to find strong associated metal materials will be indium tin oxide very possible alternatives. At present, the price of indium is about $750 per kilogram, while vanadate strontium (ca) element to the ground Shell reserves more; Vanadium sells for about $25 per kilogram, calcium and strontium more cheap than vanadium. "Strong associated metal film is similar to the structure of indium tin oxide film. From the point of our understanding, vanadate strontium (ca) all can use the same manufacturing equipment production." Engel - Herbert said.
At the same time, the nature - the material editor invited inorganic chemistry and solid state chemistry branch of the American chemical society, northwestern university, chairman of the catalysis and surface science research center director professor Kenneth kendrick pell mayer, northwestern university materials scientist James dimitri DE Boer, professor for article writing press releases, and publish in the news and outlook of the parts. Professor Kenneth pearl pell mayer and James dimitri DE Boer, the professor spoke highly of the work, they think zhang and engel - Herbert's articles, has successfully for the first time since 1977 by shannon, doped semiconductor to design the principle of transparent conductive material, after long-term follow this line of thinking for the challenge by people, and from the experiment and theory proved that the eigen strong associated metal can also be used as a transparent conductive material.
