12-02 :: February/March 2012

nanotimes News in Brief

melted at about 1,500° C (2,732° F), then cooled down and finely cut up. Then the glass is melted again and cooled down again. Finally, nanocrystals are generated by controlled heating to about 1,000° C (1,832° F).

The secret of the Jena glass ceramic lies in its consi- stence of nanocrystals. The size of these is at most 100nm in general. “They are too small to strongly disperse light and therefore the ceramic looks translucent, like a natural tooth,” Prof. Rüssel says.

MarcDittmer, Christian Rüssel: Colorlessandhigh strength MgO/Al2

O3 /SiO2 glass-ceramic dental material using

zirconia as nucleating agent, In: Journal of Biomedical Materials Research, Vol. 100B(2012), Issue 2, February 2012, Pages 463-470, DOI:10.1002/jbm.b.31972: http://dx.doi.org/10.1002/jbm.b.31972

Researcher at Ludwig-Maximilians-University (LMU) in Munich, TU Dortmund, University of Oldenburg, and Wuppertal University, Germany, have come up with a strategy for improving the electrical properties of organic semiconductors.

They basically consist of two components, a poly- mer, which transfers an electron when it absorbs a quantum of light, and a so-called fullerene, which accepts the electron. This charge-transfer event constitutes the essential first step in the generation of electricity from light, which requires the separa- tion of negatively charged electrons from positively charged holes. “In order to improve the efficiency of organic solar cells, we need to understand and optimize the process of charge transfer at the in-

Researchers in UK and Republic of Korea made great advance in predicting polymer processing. They describe for the first time, the in silico design, synthesis, and characterization of an architecturally complex, branched polymer with the optimal rheo- logical properties for such structure-property corre- lation studies. Moreover, they demonstrate unequi- vocally the need for accurate characterization using temperature gradient interaction chromatography (TGIC), which reveals the presence of heterogenei- ties in the molecular structure that are undetectable by size exclusion chromatography (SEC). Lian R. Hutchings, Solomon M. Kimani, David M. Hoy- le, Daniel J. Read, Chinmay Das, Thomas C. B. McLeish, Taihyun Chang, Hyojoon Lee, and Dietmar Auhl: In Si- lico Molecular Design, Synthesis, Characterization, and Rheology of Dendritically Branched Polymers: Closing the Design Loop, In: ACS Macro Letters AOP, March 01, 2012, Pages 404-408, DOI:10.1021/mz300059k: http://dx.doi.org/10.1021/mz300059k

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terface between polymer and fullerene,” Da Como explains.

Felix Deschler, Enrico Da Como, Thomas Limmer, Rapha- el Tautz, Tillmann Godde, Manfred Bayer, Elizabeth von Hauff, Seyfullah Yilmaz, Sybille Allard, Ullrich Scherf, and Jochen Feldmann: Reduced Charge Transfer Exciton Re- combination in Organic Semiconductor Heterojunctions by Molecular Doping, In: Physical Review Letters, Vol. 107(2011), Issue 12, September 16, 2011, Article 127402 [4 pages], DOI:10.1103/PhysRevLett.107.127402: http://dx.doi.org/10.1103/PhysRevLett.107.127402