Energy Focus: Quantum dot layer fine-tuned for higher efficiency QLEDs
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ight-emitting devices (LEDs) using semiconductor film architectures and technologies are generally preferred over quantum dot emitters (QLEDs) due to their higher luminous power efficiencies. However, QLEDs offer a number of significant advantages, including the ability to tune the emission wavelength according to particle size, and narrow bandwidth emission. Several device designs have attempted to optimize important charge injection and transport properties of QLEDs through chemical and engineering approaches. Recently, B.S. Mashford of QD Vision, Inc., V. Bulovic and M. Bawendi of the Massachusetts Institute of Technology, and their colleagues have developed an inverted hybrid organic–inorganic device using colloidal CdSe–CdS core–shell
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2013 L’ORÉAL-UNESCO Awards for Women in Science honors materials researchers
Courtesy Julian Dufort
Each year, five outstanding women scientists—one per continent—are honored for the contributions of their research, the strength of their commitments, and their impact on society. This year, the research of the 2013 Laureates demonstrates exceptionally original approaches to fundamental research in the physical sciences with a notable relation to materials research. The award recipients include Marcia Barbosa of the Federal University of Rio Grande do Sul, Porto Alegre (Brazil) for “discovering one of the peculiarities of water which may lead to better understanding of how earthquakes occur and how proteins fold which is important for the treatment of diseases.” Water can behave in unusual and unex-
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the opposite behavior with a fast rise in intensity, followed by a much longer decay process. The researchers explain this contrast through an ultrafast charge transfer, which is facilitated by the wellaligned electronic levels between layers, as evidenced by surface potential measurements showing small variations (~0.1 V). This energy-level alignment and device stability is facilitated through the use of a ZnO nanocrystalline film for the electron-injection layer, which has previously shown promise in organic–inorganic hybrid devices. This work demonstrates the feasibility of fabricating solution-processed QLEDs with luminous efficiencies that could compete with current state-of-the-art LEDs. These detailed studies also further develop the understanding of several important photophysics processes, which can find applications in other areas of technology. Christopher Patridge
pected ways, and pinpointing exactly how water acts, and why, when it does the unexpected is key to advancing knowledge in nearly every field of science. Pratibha Gai of the University of York (United Kingdom) received the award for “ingeniously modifying her electron microscope so that she was able to observe chemical reactions occurring at surface atoms of catalysts which will help scientists in their development of new medicines or new energy sources.” Her modification and development of the atomic resolution-environmental transmi
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