Advanced Materials (Adv Mater)

Publications in this journal

• Article: Charge Density Dependent Mobility of Organic Hole-Transporters and Mesoporous TiO2 Determined by Transient Mobility Spectroscopy: Implications to Dye-Sensitized and Organic Solar Cells.

  Tomas Leijtens, Jongchul Lim, Joël Teuscher, Taiho Park, Henry J Snaith
  [show abstract] [hide abstract]
  ABSTRACT: Transient mobility spectroscopy (TMS) is presented as a new tool to probe the charge carrier mobility of commonly employed organic and inorganic semiconductors over the relevant range of charge densities. The charge density dependence of the mobility of semiconductors used in hybrid and organic photovoltaics gives new insights into charge transport phenomena in solid state dye sensitized solar cells.
  Advanced Materials 05/2013;
• Article: Highly Ordered MnO2 Nanopillars for Enhanced Supercapacitor Performance.

  Zenan Yu, Binh Duong, Danielle Abbitt, Jayan Thomas
  [show abstract] [hide abstract]
  ABSTRACT: This report demonstrates a simple, but efficient method to print highly ordered nanopillars without the use of sacrificial templates or any expensive equipment. The printed polymer structure is used as a scaffold to deposit electrode material (manganese dioxide) for making supercapacitors. The simplicity of the fabrication method together with superior power density and energy density make this supercapacitor electrode very attractive for the next generation energy storage systems.
  Advanced Materials 05/2013;
• Article: Cobalt-Substituted Magnetite Nanoparticles and Their Assembly into Ferrimagnetic Nanoparticle Arrays.

  Yongsheng Yu, Adriana Mendoza-Garcia, Bo Ning, Shouheng Sun
  [show abstract] [hide abstract]
  ABSTRACT: A simple process to prepare monodisperse ferrimagnetic cobalt-substituted magnetite Cox Fe3-x O4 nanoparticles is reported. These ferrimagnetic nanoparticles are readily dispersed in hexane, forming a stable ferrimagnetic nanoparticle dispersion, and allowing easy nanoparticle self-assembly. When assembled under an external magnetic field (5.5 kOe), these nanoparticles show preferred magnetic alignment with their Hc reaching 2.49 kOe.
  Advanced Materials 04/2013;
• Article: Localization of Folds and Cracks in Thin Metal Films Coated on Flexible Elastomer Foams.

  Hugues Vandeparre, Qihan Liu, Ivan R Minev, Zhigang Suo, Stéphanie P Lacour
  [show abstract] [hide abstract]
  ABSTRACT: Thin metal films coated on soft elastomeric foam substrates exhibit enhanced electromechanical performance. The open-cell foam structure conveys highly anisotropic mechanical properties within the top, thin capping elastomer at the surface of the foam. Upon stretching, large strain fields inducing cracks and folds localize above the foam cells, while the surrounding cell ligaments remain almost strain-free enabling stable electrical conduction in the metallic coating.
  Advanced Materials 04/2013;
• Article: One-Dimensional CdS Nanostructures: A Promising Candidate for Optoelectronics.

  Huiqiao Li, Xi Wang, Junqi Xu, Qi Zhang, Yoshio Bando, Dmitri Golberg, Ying Ma, Tianyou Zhai
  [show abstract] [hide abstract]
  ABSTRACT: As a promising candidate for optoelectronics, one-dimensional CdS nanostructures have drawn great scientific and technical interest due to their interesting fundamental properties and possibilities of utilization in novel promising optoelectronical devices with augmented performance and functionalities. This progress report highlights a selection of important topics pertinent to optoelectronical applications of one-dimensional CdS nanostructures over the last five years. This article begins with the description of rational design and controlled synthesis of CdS nanostructure arrays, alloyed nanostructucures and kinked nanowire superstructures, and then focuses on the optoelectronical properties, and applications including cathodoluminescence, lasers, light-emitting diodes, waveguides, field emitters, logic circuits, memory devices, photodetectors, gas sensors, photovoltaics and photoelectrochemistry. Finally, the general challenges and the potential future directions of this exciting area of research are highlighted.
  Advanced Materials 04/2013;
• Article: An All-Optical, Non-volatile, Bidirectional, Phase-Change Meta-Switch.

  Behrad Gholipour, Jianfa Zhang, Kevin F Macdonald, Daniel W Hewak, Nikolay I Zheludev
  [show abstract] [hide abstract]
  ABSTRACT: Non-volatile, bidirectional, all-optical switching in a phase-change metamaterial delivers high-contrast transmission and reflection modulation at near- to mid-infrared wavelengths in device structures down to ≈(1) /27 of a wavelength thick.
  Advanced Materials 04/2013;
• Article: Transit Phenomena in Organic Field-Effect Transistors Through Kelvin-Probe Force Microscopy.

  Christian Melzer, Christopher Siol, Heinz von Seggern
  [show abstract] [hide abstract]
  ABSTRACT: The temporal evolution of the surface-potential distribution in the channel of pentacene based field-effect transistors is investigated during the charge reversal from the electron to the hole dominated operation. This measurement allows for the determination of the carrier density and electric field dependent hole mobility in the sub-threshold regime of the transistor.
  Advanced Materials 04/2013;
• Article: Triple Junction Polymer Solar Cells for Photoelectrochemical Water Splitting.

  Serkan Esiner, Harm van Eersel, Martijn M Wienk, René A J Janssen
  [show abstract] [hide abstract]
  ABSTRACT: A triple junction polymer solar cell in a novel 1 + 2 type configuration provides photoelectrochemical water splitting in its maximum power point at V ≈ 1.70 V with an estimated solar to hydrogen energy conversion efficiency of 3.1%. The triple junction cell consists of a wide bandgap front cell and two identical small bandgap middle and back cells.
  Advanced Materials 04/2013;
• Article: Exciton Dynamics in Semiconductor Nanocrystals.

  Damon A Wheeler, Jin Z Zhang
  [show abstract] [hide abstract]
  ABSTRACT: This review article provides an overview of recent advances in the study and understanding of dynamics of excitons in semiconductor nanocrystals (NCs) or quantum dots (QDs). Emphasis is placed on the relationship between exciton dynamics and optical properties, both linear and nonlinear. We also focus on the unique aspects of exciton dynamics in semiconductor NCs as compared to those in bulk crystals. Various experimental techniques for probing exciton dynamics, particularly time-resolved laser methods, are reviewed. Relevant models and computational studies are also briefly presented. By comparing different materials systems, a unifying picture is proposed to account for the major dynamic features of excitons in semiconductor QDs. While the specific dynamic processes involved are material-dependent, key processes can be identified for all the materials that include electronic dephasing, intraband relaxation, trapping, and interband recombination of free and trapped charge carriers (electron and hole). Exciton dynamics play a critical role in the fundamental properties and functionalities of nanomaterials of interest for a variety of applications including optical detectors, solar energy conversion, lasers, and sensors. A better understanding of exciton dynamics in nanomaterials is thus important both fundamentally and technologically.
  Advanced Materials 04/2013;
• Article: GaP-ZnS Solid Solutions: Semiconductors for Efficient Visible Light Absorption and Emission.

  Judy N Hart, Neil L Allan
  [show abstract] [hide abstract]
  ABSTRACT: GaP-ZnS solid solutions and multilayered structures have a tunable direct band gap in the energy range for absorption and emission of visible light. A direct band gap of around 2.0 eV, the optimum for photocatalysis of water splitting, is readily accessible with these systems.
  Advanced Materials 04/2013;
• Article: Semiconducting Single-Walled Carbon Nanotubes on Demand by Polymer Wrapping.

  Widianta Gomulya, Guadalupe Diaz Costanzo, Elton J Figueiredo de Carvalho, Satria Zulkarnaen Bisri, Vladimir Derenskyi, Martin Fritsch, Nils Fröhlich, Sybille Allard, Pavlo Gordiichuk, Andreas Herrmann, Siewert Jan Marrink, Maria Cristina Dos Santos, Ulrich Scherf, Maria Antonietta Loi
  [show abstract] [hide abstract]
  ABSTRACT: Efficient selection of semiconducting SWCNTs of large diameter range (0.8-1.6 nm) on demand is demonstrated. Different diameters of SWCNT are systematically selected by tuning the alkyl side-chain lengths of the wrapping polymers of similar backbone. The exceptional quality and high concentration of the SWCNTs is validated by the outstanding optical properties and the highly performing random network ambipolar field-effect transistors.
  Advanced Materials 04/2013;
• Article: Micro/Nanometer-Scale Fiber with Highly Ordered Structures by Mimicking the Spinning Process of Silkworm.

  Su-Kyoung Chae, Edward Kang, Ali Khademhosseini, Sang-Hoon Lee
  [show abstract] [hide abstract]
  ABSTRACT: A new method for the microfluidic spinning of ultrathin fibers with highly ordered structures is proposed by mimicking the spinning mechanism of silkworms. The self-aggregation is driven by dipole-dipole attractions between polar polymers upon contact with a low-polarity solvent to form fibers with nanostrands. The induction of Kelvin-Helmholtz instabilities at the dehydrating interface between two miscible fluids generates multi-scale fibers in a single microchannel.
  Advanced Materials 04/2013;
• Article: UV-Visible Spectroscopic Analysis of Electrical Properties in Alkali Metal-Doped Amorphous Zinc Tin Oxide Thin-Film Transistors.

  Keon-Hee Lim, Kyongjun Kim, Seonjo Kim, Si Yun Park, Hyungjun Kim, Youn Sang Kim
  [show abstract] [hide abstract]
  ABSTRACT: Solution-processed and alkali metals, such as Li and Na, are introduced in doped amorphous zinc tin oxide (ZTO) semiconductor TFTs, which show better electrical performance, such as improved field effect mobility, than intrinsic amorphous ZTO semiconductor TFTs. Furthermore, by using spectroscopic UV-visible analysis we propose a comprehensive technique for monitoring the improved electrical performance induced by alkali metal doping in terms of the change in optical properties. The change in the optical bandgap supported by the Burstein-Moss theory could successfully show a mobility increase that is related to interstitial doping of alkali metal in ZTO semiconductors.
  Advanced Materials 04/2013;
• Article: Thermally Assisted All-Optical Helicity Dependent Magnetic Switching in Amorphous Fe100-x Tbx Alloy Films.

  Alexander Hassdenteufel, Birgit Hebler, Christian Schubert, Andreas Liebig, Martin Teich, Manfred Helm, Martin Aeschlimann, Manfred Albrecht, Rudolf Bratschitsch
  [show abstract] [hide abstract]
  ABSTRACT: All-optical switching (AOS) in ferrimagnetic Fe100-x Tbx alloys is presented. AOS is witnessed below, above, and in samples without a magnetic compensation point. It is found that AOS is associated with laser heating up to the Curie temperature and intimately linked to a low remanent sample magnetization. Above a threshold magnetization of 220 emu/cc helicity dependent AOS is replaced by pure thermal demagnetization.
  Advanced Materials 04/2013;
• Article: High-Throughput Analytical Model to Evaluate Materials for Temperature Swing Adsorption Processes.

  Julian P Sculley, Wolfgang M Verdegaal, Weigang Lu, Mario Wriedt, Hong-Cai Zhou
  [show abstract] [hide abstract]
  ABSTRACT: In order for any material to be considered in a post-combustion carbon capture technology, it must have high working capacities of CO2 from flue gas and be regenerable using as little energy as possible. Shown here is an easy to use method to calculate both working capacities and regeneration energies and thereby predict optimal desorption conditions for any material.
  Advanced Materials 04/2013;
• Article: Light Propagation in High-Spin Organic Microtubes Self-Assembled from Shape Persistent Macrocycles Carrying Oxo-Verdazyl Biradicals.

  Pramiti Hui, Rajadurai Chandrasekar
  [show abstract] [hide abstract]
  ABSTRACT: A 1D paramagnetic organic tube self-assembled from a "clicked" shape-persistent macrocycle carrying high-spin oxoverdazyl biradicals shows optical wave guiding behavior.
  Advanced Materials 04/2013;
• Article: Flexible Low-Voltage Organic Transistors with High Thermal Stability at 250 °C.

  Tomoyuki Yokota, Kazunori Kuribara, Takeyoshi Tokuhara, Ute Zschieschang, Hagen Klauk, Kazuo Takimiya, Yuji Sadamitsu, Masahiro Hamada, Tsuyoshi Sekitani, Takao Someya
  [show abstract] [hide abstract]
  ABSTRACT: Low-operating-voltage flexible organic thin-film transistors with high thermal stability using DPh-DNTT and SAM gate dielectrics are reported. The mobility of the transistors are decreased by 23% after heating to 250 °C for 30 min. Furthermore, flexible organic pseudo-CMOS inverter circuits, which are functional after heating to 200 °C.
  Advanced Materials 04/2013;
• Article: High-Power Density Piezoelectric Energy Harvesting Using Radially Strained Ultrathin Trigonal Tellurium Nanowire Assembly.

  Tae Il Lee, Sangmin Lee, Eungkyu Lee, Sungwoo Sohn, Yean Lee, Sujeong Lee, Geondae Moon, Dohyang Kim, Youn Sang Kim, Jae Min Myoung, Zhong Lin Wang
  [show abstract] [hide abstract]
  ABSTRACT: A high-yield solution-processed ultrathin (<10 nm) trigonal tellurium (t-Te) nanowire (NW) is introduced as a new class of piezoelectric nanomaterial with a six-fold higher piezoelectric constant compared to conventional ZnO NWs for a high-volume power-density nanogenerator (NG). While determining the energy-harvesting principle in a NG consisting of t-Te NW, we theoretically and experimentally found that t-Te NW is piezoelectrically activated only by creating strain in its radial direction, along which it has an asymmetric crystal structure. Based upon this mechanism, we fabricated a NG with a monolayer consisting of well-aligned t-Te NWs and demonstrated a NG with a power density of 9 mW/cm(3) .
  Advanced Materials 04/2013;
• Article: Controlling liquid spreading using microfabricated undercut edges (adv. Mater. 16/2013).

  Ville Liimatainen, Veikko Sariola, Quan Zhou
  [show abstract] [hide abstract]
  ABSTRACT: A purely topographical structure can be used for controlling liquid spreading on surfaces, as reported by Quan Zhou and co-workers on page 2275. The method exploits easy-to-fabricate undercut edges to confine micro- and macroscale droplets and to control surface-microfluidic flow. The edges exhibit close to 180° contact angles even for low surface tension liquids, leading to highly anisotropic wetting at large scale.
  Advanced Materials 04/2013; 25(16):2274.