- Bottom-up Assembly of Nanoporous Graphene with Emergent Electronic States
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The incorporation of nanoscale pores into a sheet of graphene allows it to switch from an impermeable semimetal to a semiconducting nanosieve. Nanoporous graphenes are desirable for applications ranging from high-performance semiconductor device channels to atomically thin molecular sieve membranes, and their performance is highly dependent on the periodicity and reproducibility of pores at the atomic level. Achieving precise nanopore topologies in graphene using top-down lithographic approaches has proven to be challenging due to poor structural control at the atomic level. Alternatively, atomically precise nanometer-sized pores can be fabricated via lateral fusion of bottom-up synthesized graphene nanoribbons. This technique, however, typically requires an additional high temperature cross-coupling step following the nanoribbon formation that inherently yields poor lateral conjugation, resulting in 2D materials that are weakly connected both mechanically and electronically. Here, we demonstrate a novel bottom-up approach for forming fully conjugated nanoporous graphene through a single, mild annealing step following the initial polymer formation. We find emergent interface-localized electronic states within the bulk band gap of the graphene nanoribbon that hybridize to yield a dispersive two-dimensional low-energy band of states. We show that this low-energy band can be rationalized in terms of edge states of the constituent single-strand nanoribbons. The localization of these 2D states around pores makes this material particularly attractive for applications requiring electronically sensitive molecular sieves.
- Jacobse, Peter H.,McCurdy, Ryan D.,Jiang, Jingwei,Rizzo, Daniel J.,Veber, Gregory,Butler, Paul,Zuzak, Rafa?,Louie, Steven G.,Fischer, Felix R.,Crommie, Michael F.
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- Large-Cavity Coronoids with Different Inner and Outer Edge Structures
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Coronoids, polycyclic aromatic hydrocarbons with geometrically defined cavities, are promising model structures of porous graphene. Here, we report the on-surface synthesis of C168 and C140 coronoids, referred to as [6]- and [5]coronoid, respectively, usi
- Di Giovannantonio, Marco,Eimre, Kristjan,Fasel, Roman,Müllen, Klaus,Narita, Akimitsu,Pignedoli, Carlo A.,Ruffieux, Pascal,Urgel, José I.,Yao, Xuelin
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- Bicarbazole derivatives and organic light emitting device thereof
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The invention provides bicarbazole derivatives and an organic light emitting device thereof, and belongs to the technical field of organic light emitting materials. The bicarbazole derivatives solve technical problems in the prior art that luminous performance is poor, for example, luminous efficiency is low, and service life is short. According to the invention, 3 and 3' positions of two carbazole structures are connected to form a bicarbazole structure, charge carrier injection balance is improved through adjusting groups of R1, R2, Ar1, and Ar2, and the recombination ratio of electrons andelectron holes in a luminous layer is improved. The bicarbazole derivatives provided by the invention can be used for the organic light emitting device, and especially used as host materials of a luminescent layer in the organic light-emitting device to exhibit the advantages of higher luminous efficiency and obviously-increased service life; and the organic light emitting device provided by the invention is superior to a current common OLED (organic light emitting diode) device.
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Paragraph 0046; 0047; 0048; 0049
(2018/04/03)
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- COMPOUND FOR ORGANIC ELECTROLUMINESCENT DEVICE AND ORGANIC ELECTROLUMINESCENT DEVICE INCLUDING THE SAME
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This invention relates to a compound for an organic electroluminescent device and to an organic electroluminescent device including the same. This compound for the organic electroluminescent device including the same is improved in thermal stability and l
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Paragraph 0110-0111; 0113-0114
(2018/05/15)
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- 2,6-Bis(phenylethynyl)biphenyls and their cyclization to pyrenes
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We present a new protocol for pyrene synthesis via transition-metal cross-couplings. The initially prepared 2,6-bis(phenylethynyl)biphenyls were transformed to pyrenes with uncommon 4,10-disubstitution through an electrophilic cyclization. The precursors were synthesized by Suzuki-Miyaura cross-coupling, which provides 2,6-dibromobiphenyls; these were subsequently coupled with phenylethynyl derivatives via Kumada cross-coupling. Georg Thieme Verlag Stuttgart · New York.
- MacHuy, Mareike M.,Wuertele, Christian,Schreiner, Peter R.
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experimental part
p. 1405 - 1409
(2012/07/02)
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- Process for the preparation of bromoarylacetylene and aryldiacetylene precursors
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Bromoarylacetylenes such as m-bromophenylacetylene and certain precursors to such bromoarylacetylene are prepared by reacting an aryldibromide with a substituted terminal acetylene compound containing at least three carbon atoms and a hydroxy group on the carbon atom adjacent to the acetylene group in the presence of a dialkyl or trialkyl amine solvent and a catalyst system consisting of a palladium complex containing two halogen moieties and two tri-substituted phosphine moieties. Additional triphenylphosphine can be added. A cuprous iodide promoter is also employed in the reaction sequence. The bromoarylacetylenes can be reacted with a substituted terminal acetylene compound as defined using the same catalyst system as defined to produce the corresponding aryldihydroxy substituted acetylenes. Certain bromophenylhydroxy substituted acetylenes are claimed as new compositions.
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