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Lü,, Minfeng,Jo, Hongil,Oh, Seung-Jin,Lee, Suheon,Choi, Kwang-Yong,Yu, Yang,Ok, Kang Min ACS AMERICAN CHEMICAL SOCIETY 2017 Inorganic Chemistry Vol.56 No.10
<P>Three new quaternary lithium metal tellurites, Li3MTe4O11 (M = Al, Ga, and Fe), have been synthesized through hydrothermal and solid-state reactions by heating a mixture of LiOH center dot H2O, TeO2, and M2O3. The structures of the title compounds have been determined by single-crystal and powder X-ray diffraction. Li3MTe4O11 reveal three-dimensional (3D) frameworks that consist of MO6 octahedra, TeO3 trigonal pyramids, and TeO4 polyhedra. The variable coordination mode of Te4+ within the framework leads to the formation of 1D channels that host Li+ cations on both tetrahedral and octahedral sites. The bulk and grain boundary Li+ ion conductivities for a Li3FeTe4O11 pellet in open air are estimated to be 1.0 x 10(-4) and 2.7 x 10(-6) S cm(-1), respectively, at room temperature from the impedance profile analysis. A lower activation energy of 19.9 kJ mol(-1) is obtained for the system, which is similar to that of Li10GeP2S12 (24 kJ mol(-1)). Detailed characterizations such as thermal, spectroscopic, and magnetic properties for the reported materials are also reported.</P>
Organic Zener Diodes: Tunneling across the Gap in Organic Semiconductor Materials
Kleemann, Hans,Gutierrez, Rafael,Lindner, Frank,Avdoshenko, Stanislav,Manrique, Pedro D.,Lü,ssem, Bjox308,rn,Cuniberti, Gianaurelio,Leo, Karl American Chemical Society 2010 Nano letters Vol.10 No.12
<P>Organic Zener diodes with a precisely adjustable reverse breakdown from −3 to −15 V without any influence on the forward current−voltage curve are realized. This is accomplished by controlling the width of the charge depletion zone in a pin-diode with an accuracy of one nanometer independently of the doping concentration and the thickness of the intrinsic layer. The breakdown effect with its exponential current voltage behavior and a weak temperature dependence is explained by a tunneling mechanism across the highest occupied molecular orbital−lowest unoccupied molecular orbital gap of neighboring molecules. The experimental data are confirmed by a minimal Hamiltonian model approach, including coherent tunneling and incoherent hopping processes as possible charge transport pathways through the effective device region.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2010/nalefd.2010.10.issue-12/nl102916n/production/images/medium/nl-2010-02916n_0005.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl102916n'>ACS Electronic Supporting Info</A></P>
Source Forensics of Black Carbon Aerosols from China
Chen, Bing,Andersson, August,Lee, Meehye,Kirillova, Elena N.,Xiao, Qianfen,Krusax30a,, Martin,Shi, Meinan,Hu, Ke,Lu, Zifeng,Streets, David G.,Du, Ke,Gustafsson, Ox308,rjan American Chemical Society 2013 Environmental science & technology Vol.47 No.16
<P>The limited understanding of black carbon (BC) aerosol emissions from incomplete combustion causes a poorly constrained anthropogenic climate warming that globally may be second only to CO<SUB>2</SUB> and regionally, such as over East Asia, the dominant driver of climate change. The relative contribution to atmospheric BC from fossil fuel versus biomass combustion is important to constrain as fossil BC is a stronger climate forcer. The source apportionment is the underpinning for targeted mitigation actions. However, technology-based “bottom-up” emission inventories are inconclusive, largely due to uncertain BC emission factors from small-scale/household combustion and open burning. We use “top-down” radiocarbon measurements of atmospheric BC from five sites including three city sites and two regional sites to determine that fossil fuel combustion produces 80 ± 6% of the BC emitted from China. This source-diagnostic radiocarbon signal in the ambient aerosol over East Asia establishes a much larger role for fossil fuel combustion than suggested by all 15 BC emission inventory models, including one with monthly resolution. Our results suggest that current climate modeling should refine both BC emission strength and consider the stronger radiative absorption associated with fossil-fuel-derived BC. To mitigate near-term climate effects and improve air quality in East Asia, activities such as residential coal combustion and city traffic should be targeted.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/esthag/2013/esthag.2013.47.issue-16/es401599r/production/images/medium/es-2013-01599r_0005.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/es401599r'>ACS Electronic Supporting Info</A></P>
Shi, Junqing,Aguilar Suarez, Luis E.,Yoon, Seong-Jun,Varghese, Shinto,Serpa, Carlos,Park, Soo Young,Lü,er, Larry,Roca-Sanjuax301,n, Daniel,Miliax301,n-Medina, Begonx303,a,Gierschner, Johan American Chemical Society 2017 JOURNAL OF PHYSICAL CHEMISTRY C - Vol.121 No.41
<P>Solid state luminescence enhancement (SLE) of conjugated organic materials has had a great impact in materials science, but a deep understanding has been rather limited to date. Here, we investigate a prototype example of SLE materials, cyano-substituted distyrylbenzene (DCS), by varying systematically and subtly the substitution pattern (inter alia of the position of the cyano-substituent) to give largely different photoresponse in fluid and solid solution as well in the crystalline state. The combination of quantitative (ultra)fast optical spectroscopic techniques, appropriate quantum-chemical methods, and structural (X-ray) data allows us to elucidate and rationalize all details of the SLE process, including steric versus electronic factors, radiative versus nonradiative decay channels, and intra- versus intermolecular contributions, providing a first holistic picture of SLE.</P>
Song, Yuna,Kim, Youngmu,Noh, Yeonjin,Singh, Varun Kumar,Behera, Santosh Kumar,Abudulimu, Abasi,Chung, Kyeongwoon,Wannemacher, Reinhold,Gierschner, Johannes,Lü,er, Larry,Kwon, Min Sang American Chemical Society 2019 Macromolecules Vol.52 No.15
<P>A highly efficient organic photocatalyst (OPC) for photoinduced electron/energy-transfer reversible addition-fragmentation chain-transfer (PET-RAFT) polymerization was identified through a systematic catalyst design and discovery. The devised OPC offers excellent control over PET-RAFT polymerizations of methyl methacrylate at very low catalyst loadings (5 ppm), that is, ca. 5-50 times lower loadings than other OPCs reported so far. Moreover, excellent oxygen tolerance was achieved using the discovered OPC combined with trithiocarbonate-based chain-transfer agent (CTA) under low-energy light irradiation conditions. In depth experimental and computational investigations revealed that (1) strong visible-light absorption and efficient generation of long-lived triplet states of the OPC due to its unique molecular structure and (2) the oxidation stability and no rate retardation of trithiocarbonate-based CTA are the key to the outstanding oxygen tolerance and ppm-level catalyst loadings. Our approach is thus believed to address a variety of challenging tasks related to polymer synthesis and living additive manufacturing.</P> [FIG OMISSION]</BR>