Photosensitive Nanocomposites

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www.advmat.de Photosensitive Nanocomposites Baohua Jia, Min Gu, and co-workers report on p.

The cover image shows functional three-dimensional micro/ nano photonic structures, for example, photonic crystals can be fabricated in such active nanocomposites using the versatile two-photon

Advanced Functional Materials is the number one full-paper journal in materials science with a 2007 ISI Impact Factor of 7.496.

Publishing every two weeks in 2009 with articles available online in advance of print, AFM is your gateway to the full story in materials science. www.afm-journal.

1 Photosensitive Nanocomposites Baohua Jia, Min Gu, and co-workers report on p on novel quantum dot functionalized photosensitive nanocomposites showing ultrahigh third-order nonlinearity. The cover image shows functional three-dimensional micro/ nano photonic structures, for example, photonic crystals can be fabricated in such active nanocomposites using the versatile two-photon polymerisation method, opening various possibilities in active micro/nano devices, such as ultrafast switching, signal regeneration, and high speed demultiplexing systems. Advanced Functional Materials is the number one full-paper journal in materials science with a 2007 ISI Impact Factor of AFM publishes high-quality, in-depth Full Papers on the development and application of functional materials and Feature Articles reviewing the hottest research topics. Publishing every two weeks in 2009 with articles available online in advance of print, AFM is your gateway to the full story in materials science. Graphene Oxide For over 150 years, oxidation of graphite has been known to result in water-soluble graphite oxide. However, it has been only recently recognized that graphite oxide splits into atomically thin graphene oxide (GO) upon dissolution. GO can be produced on a large scale, handled in solution, assembled into thin films, and deposited on arbitrary substrates. Manish Chhowalla and Goki Eda review on p fundamenta properties of graphene oxide (GO) and summarize recent achievements in device applications. Valanoor Nagarajan and co-workers demonstrate on p that long-range strain fields associated with dislocation cores at an oxide interface are shown to be sufficient enough to create significant variations in the chemical composition around the core (Cottrell atmospheres). Such stress-assisted diffusion of cations towards the cores is proposed to significantly impact the properties of nanoscale functional devices. The figure shows a Z-contrast image of a single dislocation core at an oxide interface. Small is the very best interdisciplinary forum for all experimental and theoretical aspects of fundamental and applied research at the micro and nano length scales. With an ISI Impact Factor of and publishing every two weeks in 2009 with papers online in advance of print, Small is your first-choice venue for top-quality communications, detailed full papers, cutting-edge concepts, and in-depth reviews of all things micro and nano. Adv. Mater. 2010, 22, 2387 # 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 2387

graphite oxide. However, it has been only recently recognized that graphite oxide splits into atomically thin graphene oxide (GO) upon dissolution.

This Review introduces fundamental properties of GO and summarizes recent achievements in device applications. Liquid Crystals Y. H. Kim, J.-O. Lee, H. S. Jeong, J. H. Kim, E. K. Yoon, D. K. Yoon, J.

..2416 2420 Optically Selective Microlens Photomasks Using Self-Assembled Smectic Liquid Crystal Defect Arrays A photomask that combines two imaging elements (microlens arrays and clear windows) in

2 REVIEW Graphene G. Eda, M. Chhowalla* Chemically Derived Graphene Oxide: Towards Large-Area Thin-Film Electronics and Optoelectronics For over 150 years, oxidation of graphite has been known to result in water-soluble graphite oxide. However, it has been only recently recognized that graphite oxide splits into atomically thin graphene oxide (GO) upon dissolution. GO can be produced on a large scale, handled in solution, assembled into thin films, and deposited on arbitrary substrates. This Review introduces fundamental properties of GO and summarizes recent achievements in device applications. Liquid Crystals Y. H. Kim, J.-O. Lee, H. S. Jeong, J. H. Kim, E. K. Yoon, D. K. Yoon, J.-B. Yoon, H.-T. Jung* Optically Selective Microlens Photomasks Using Self-Assembled Smectic Liquid Crystal Defect Arrays A photomask that combines two imaging elements (microlens arrays and clear windows) in one structure has been developed by using toric focal conic domain (TFCD) micro arrays of smectic liquid crystals. Their application as optically selective photomasks by simply adjusting (i) the illumination dose, (ii) the size of TFCD array mask, and (iii) the tone of photoresist (PR) is demonstrated (see figure). Nanodots G.-S. Park,* H. Kwon, E. K. Lee, S. K. Kim, J. H. Lee, X. S. Li, J. G. Chung, S. Heo, I. Y. Song, J. H. Lee, B. L. Choi, J. M. Kim Fabrication of Surface Plasmon-Coupled Si Nanodots in Au-Embedded Silicon Oxide Nanowires High-density amorphous silicon nanodots are easily produced by irradiating goldnanoparticle-embedded silicon oxide nanowires with a low-intensity electron beam. The optical characteristics of Si nanodots in the vicinity of gold nanoparticles exhibit evidence of strong coupling to the surface plasmon resonance of the Au nanoparticles, as manifested by their markedly enhanced electron-induced excitation in our monochromated scanning transmission electron microscopy electron energyloss spectroscopy measurements. Patterned Nanostructures P. Kim, R. Kwak, S. H. Lee, K. Y. Suh* Solvent-Assisted Decal Transfer Lithography by Oxygen-Plasma Bonding and Anisotropic Swelling Solvent-assisted decal transfer lithography (DTL) enables the formation of welldefined micro-/nanostructures over a large area (4 in. wafer) by combining irreversible oxygen bonding and anisotropic swelling of poly(dimethoxylsiloxane) (PDMS). Such swelling-induced stress gradient allows for cohesion failure of the skin layer upon removal of the stamp, leaving behind a highly uniform layer (100 nm) # 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Adv. Mater. 2010, 22,

Long-range strain fields associated with dislocation cores at an oxide interface are shown to be sufficient enough to create significant variations in the chemical composition around the core

The figure shows a Z-contrast image of a single dislocation core at an oxide interface. Ferroelectrics M. Arredondo, Q. M. Ramasse, M. Weyland, R. Mahjoub, I. Vrejoiu, D. Hesse, N. D. Browning, M.

.. 2430 2434 Direct Evidence for Cation Non-Stoichiometry and Cottrell Atmospheres Around Dislocation Cores in Functional Oxide Interfaces Atomic layer deposition (ALD) and electrodeposition are

3 Long-range strain fields associated with dislocation cores at an oxide interface are shown to be sufficient enough to create significant variations in the chemical composition around the core (Cottrell atmospheres). Such stress-assisted diffusion of cations towards the cores is proposed to significantly impact the properties of nanoscale functional devices. The figure shows a Z-contrast image of a single dislocation core at an oxide interface. Ferroelectrics M. Arredondo, Q. M. Ramasse, M. Weyland, R. Mahjoub, I. Vrejoiu, D. Hesse, N. D. Browning, M. Alexe, P. Munroe, V. Nagarajan* Direct Evidence for Cation Non-Stoichiometry and Cottrell Atmospheres Around Dislocation Cores in Functional Oxide Interfaces Atomic layer deposition (ALD) and electrodeposition are combined with a porous template to create ordered arrays of nanowires in which a nickel core and an iron oxide shell are separated by a silica spacer layer. The switching of each magnetic component is distinct and occurs at a field that depends on the tunable thicknesses of the various layers. Core/Shell Nanowires Y. T. Chong, D. Görlitz, S. Martens, M. Y. E. Yau, S. Allende, J. Bachmann,* K. Nielsch Multilayered Core/Shell Nanowires Displaying Two Distinct Magnetic Switching Events Inspired by biological ion channels, the generation of artificial nanochannels has strong implications for the simulation of different processes of ionic transport as well as enhance the functionality of biological ion channels. Here, we show plasma asymmetric chemical modification approach to prepare the ph asymmetric gating nanochannel that can achieve ph control for both different ionic rectification and perfect gating function, simultaneously. Ionic Transport X. Hou, Y. J. Liu, H. Dong, F. Yang, L. Li,* L. Jiang* A ph-gating Ionic Transport Nanodevice: Asymmetric Chemical Modification of Single Nanochannels Using neutron reflectivity, self-stratification in a model P3HT/PCBM blend is observed. The as-spun and solventannealed films show a depletion of PCBM near the top surface and enrichment of PCBM at the substrate (see figure). Depletion of PCBM at the cathode interface in a photovoltaic device could act as a barrier to efficient electron extraction. On thermal annealing, the PCBM depleted region is eliminated; an effect that partially explains the improvement of P3HT/PCBM devices on thermal annealing. Solar Cells A. J. Parnell,* A. D. F. Dunbar, A. J. Pearson, P. A. Staniec, A. J. C. Dennison, H. Hamamatsu, M. W. A. Skoda, D. G. Lidzey, R. A. L. Jones Depletion of PCBM at the Cathode Interface in P3HT/PCBM Thin Films as Quantified via Neutron Reflectivity Measurements Adv. Mater. 2010, 22, # 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Transistors Q. Lai, L. Zhang, Z. Li, W. F. Stickle, R. S. Williams, Y. Chen*.

hybrid materials to emulate biological synapses with spike signal processing, learning, and memory functions.

Temporally correlated pre- and post-synaptic spikes modify ions stored in the polymer, resulting in the nonvolatile modification of the transistor with spike-timing-dependent plasticity.

..2454 2457 Magnetic-Field-Assisted Electrospinning of Aligned Straight and Wavy Polymeric Nanofibers Aligned straight and wavy fibers of biodegradable poly(d,l-lactic-co-glycolic acid) (PLGA) are

4 Transistors Q. Lai, L. Zhang, Z. Li, W. F. Stickle, R. S. Williams, Y. Chen* Ionic/Electronic Hybrid Materials Integrated in a Synaptic Transistor with Signal Processing and Learning Functions A synaptic transistor is fabricated by integrating ionic/electronic hybrid materials to emulate biological synapses with spike signal processing, learning, and memory functions. A potential spike generates transient ionic fluxes in a polymer layer in the transistor gate, triggering an excitatory postsynaptic current in the transistor drain. Temporally correlated pre- and post-synaptic spikes modify ions stored in the polymer, resulting in the nonvolatile modification of the transistor with spike-timing-dependent plasticity. Biomedical Materials Y. Liu, X. Zhang, Y. Xia, H. Yang* Magnetic-Field-Assisted Electrospinning of Aligned Straight and Wavy Polymeric Nanofibers Aligned straight and wavy fibers of biodegradable poly(d,l-lactic-co-glycolic acid) (PLGA) are fabricated using a magnetic-field-assisted electrospinning method. PLGA fibrous matrices prepared by this method can guide the growth of pluripotent murine mesenchymal stem cells. While the stem cells on the randomly oriented fibers adapt pseudosphere-like shape, those on aligned fibers exhibit elongated morphology along the long axes (see figure). Transistors Z. Wei, W. Hong, H. Geng, C. Wang, Y. Liu, R. Li, W. Xu,* Z. Shuai,* W. Hu,* Q. Wang, D. Zhu* Organic Single Crystal Field-Effect Transistors Based on 6H-Pyrrolo[3,2 b:4,5 b]bis[1,4]benzothiazine and its Derivatives Single crystal field-effect transistors (SCFETs) are fabricated based on single crystal micro-ribbons of 6H-pyrrolo[3,2 b:4,5 b]bis[1,4]benzothiazine and its 6- substituted derivatives (PBBTZ 1 3). High mobility (3.6 cm 2 V 1 s 1 ) and high stability (no significant decrease in one year) are obtained from the devices. The quantum chemically calculated results on the crystals 1 3 (see figure) agree well with the experimental data. How to contact us: Editorial Office: Phone: (+49) /432 Fax: (+49) advmat@wiley-vch-de Reprints: cherth@wiley-vch.de Copyright Permission: Fax: (+49) rights@wiley-vch.de # 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Adv. Mater. 2010, 22,

A nanocomposite consisting of a photosensitive organic inorganic hybrid polymer functionalized with PbS quantum dots has been developed using a sol gel process.

The non-linear nanocomposite has been proven to be suitable for the fabrication of 3D micro/nano photonic devices using two-photon polymerization.

5 A nanocomposite consisting of a photosensitive organic inorganic hybrid polymer functionalized with PbS quantum dots has been developed using a sol gel process. The uniformly dispersed nanocomposite exhibits ultrahigh third-order non-linearity ( cm 2 W 1 ) because of the strong quantum confinement of smallsized and narrowly distributed quantum dots. The non-linear nanocomposite has been proven to be suitable for the fabrication of 3D micro/nano photonic devices using two-photon polymerization. The fabricated photonic crystals show stop gaps with more than 60% suppression in transmission at the telecommunications wavelength region. Photonics B. Jia,* D. Buso, J. van Embden, J. Li, M. Gu* Highly Non-Linear Quantum Dot Doped Nanocomposites for Functional Three-Dimensional Structures Generated by Two-Photon Polymerization The bipolar host material BCPO (bis-4- (N-carbazolyl)phenylphosphine oxide) containing a phosphine oxide and two carbazole groups, synthesized in three steps, shows a high triplet energy gap of 3.01 ev. The material can be used as a universal host for blue, green, and red phosphorescent devices, all giving extremely high efficiencies with turn-on voltages within 3 V. OLEDs H.-H. Chou, C.-H. Cheng* A Highly Efficient Universal Bipolar Host for Blue, Green, and Red Phosphorescent OLEDs Adv. Mater. 2010, 22, # 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Seminars in Nanosystems - I

Seminars in Nanosystems - I Winter Semester 2011/2012 Dr. Emanuela Margapoti Emanuela.Margapoti@wsi.tum.de Dr. Gregor Koblmüller Gregor.Koblmueller@wsi.tum.de Seminar Room at ZNN 1 floor Topics of the