NEWS OF TH E WEEK
SHIFTING R&D LANDSCAPE
marketplace and in economic competitiveness and have increasingly placed a priority on building their capacity in science and technology,” says Dan E. Arvizu, chairman of the National Science Board. Emerging economies’ focus on R&D is rapidly changing the scientific landscape, adds Arvizu, who is director and chief executive of the National Renewable Energy Laboratory. According to the report, in terms of global R&D expenditures in 2011, the U.S. remains the leader, holding just under a 30% share. The U.S. portion is down from 37% in 2001. One-third of global R&D expenditures came from Asia, with 15% coming from China and 10% coming from Japan. The European Union held a 22% share of global R&D in 2011, down from 26% in 2001. Looking at R&D investments as a share of gross domestic product (GDP), the U.S. ranks 10th with investments in 2011 of 2.8% of GDP. Countries with more R&D investment include South Korea with 4.0% of GDP, and Japan with 3.4% of GDP. The report finds that the U.S. still is the front-runner in many areas. These include total R&D investment, number of high-quality publications, patents issued, and income generated by intellectual property export. The report also finds that U.S. R&D has rebounded from the Great Recession, thanks in part to funding from the 2009 American Recovery & Reinvestment Act. “Science & Engineering Indicators” has been compiled every two years since 1972.—SUSAN MORRISSEY
REPORT: NSF study shows the U.S., INVESTMENTS R&D investments as a percentage of a country’s economic activity vary.
Europe, and Japan are slipping in relation to emerging economies
T
HE U.S., EUROPE, and Japan no longer mo-
nopolize the R&D arena because emerging Asian economies are expanding their share of global R&D intensity, % R&D investment. This is a 4.5 major finding of the 2014 “SciSouth Korea ence & Engineering Indica3.5 tors.” The biennial report is Japan the product of the National U.S. Science Board, the policy2.5 Germany making body for NSF and an U.K. advisory panel to Congress. 1.5 “Emerging economies unChina derstand the role science and 0.5 innovation play in the global 2001 02 03 04 05 06 07 08 09 10 11
NOTE: R&D intensity is a country’s R&D investment as a percentage of its gross domestic product (GDP). Conversions of foreign currencies to U.S. dollars are calculated with each country’s GDP implicit price deflator and with OECD purchasing-power-parity exchange rates. Data for the U.S. reflect international standards for calculating gross expenditures on R&D, which vary slightly from NSF’s protocol for tallying U.S. total R&D. SOURCE: 2014 “Science & Engineering Indicators”
EASY MOVES FOR CLEAN GRAPHENE MATERIALS: A new technique transfers
high-quality graphene sheets to devices for better performance
G
RAPHENE HAS A DIRTY little secret. When
researchers build electronic devices with it, the standard process they use to move sheets of the delicate, single-atom-thick material into place can lead to contamination or damage that reduces device performance. But now, researchers in Taiwan have developed a simple and elegant way to transfer graphene that keeps the material clean (ACS Nano 2014, DOI: 10.1021/nn406170d). Scientists produce high-quality, largearea sheets of graphene by growing them on copper surfaces using a method called chemical vapor deposition. Unfortunately, removing the graphene from the copper substrate is where the contamination problems start, says Chih-I Wu, an electrical engineer at National Taiwan University. The most commonly used transfer CEN.ACS.ORG
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ACS NANO
Using a simple new method, researchers can place a clean sheet of graphene (top) onto an organic solar cell to serve as a transparent electrode.
method relies on a polymer-based material to hold the graphene in place while the metal below is etched away. The polymer, however, leaves behind a residue that contaminates the graphene. And cleaning it often damages the graphene so it doesn’t perform optimally, Wu says. His team reports a cleaner approach that starts with submerging a copper substrate and its attached graphene in a petri dish filled with a metal-etching solution. The solution frees the graphene, which then floats on the surface. The researchers replace the etching solution with a mixture of isopropyl alcohol and water. Next, the researchers slip the device they’re building below the floating graphene sheet. The researchers then remove the alcohol-water mixture, lowering the graphene onto the device. Using this transfer method, the researchers made a series of devices, including a transparent organic solar cell and graphene-based transistors. Electrical charges could move 50% faster through the transistors than in those made with graphene transferred by polymer. Rodney S. Ruoff, a nanoengineer at the University of Texas, Austin, calls the approach interesting and useful. He suggests it could be used to make a type of lowpower transistor called a BiSFET, which ideally needs very clean graphene. The researchers plan to scale up the method and test the approach with 8- or 12-inch-diameter silicon wafers.—KATE GREENE, special to C&EN
FEBRUARY 17, 2014
