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Topological insulator nanostructures

  1. Top of page
  2. Topological insulator nanostructures
  3. Recent progress in the understanding of exciton dynamics within phosphorescent OLEDs
  4. Real-time manipulation of ZnO nanowires on a flat surface employed for tribological measurements

Judy J. Cha, Kristie J. Koski, and Yi Cui

Nanostructured topological insulators with large surface-to-volume ratios are essential in order to study and control the exotic electronic properties of the topological surface states. Following the discovery of binary chalcogenides as topological insulators, the progress in the topological insulator research field has been remarkable. In this Review@RRL, synthesis of topological insulator nanostructures, notable transport experiments, and current nanomaterial challenges together with the corresponding solutions are presented for general readers.

Part of Focus Issue on

Topological Insulators – From Materials Design to Reality

(Eds.: Claudia Felser, Shoucheng Zhang, Binghai Yan)

Phys. Status Solidi RRL (2012) DOI 10.1002/pssr.201206393

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Recent progress in the understanding of exciton dynamics within phosphorescent OLEDs

  1. Top of page
  2. Topological insulator nanostructures
  3. Recent progress in the understanding of exciton dynamics within phosphorescent OLEDs
  4. Real-time manipulation of ZnO nanowires on a flat surface employed for tribological measurements

Sebastian Reineke and Marc A. Baldo

The use of phosphorescent emitter molecules in organic light-emitting diodes (OLEDs) allows that every exciton formed in the organic emission layer(s) can emit a photon. With that, phosphorescence provides a fourfold improvement over conventional fluorescent OLEDs to unity internal quantum efficiency. In turn, the excited state lifetimes of the triplet emitters used are orders of magnitude longer than the ones of singlet excitons introducing a noticeable efficiency roll-off. In this Feature Article, Reineke and Baldo review recent progress in the understanding of phosphorescence in OLEDs. In addition, the authors discuss emerging conceptual alternatives to phosphorescence like extrafluorescence and thermally delayed fluorescence.

Phys. Status Solidi A (2012) DOI 10.1002/pssa.201228292

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Real-time manipulation of ZnO nanowires on a flat surface employed for tribological measurements

  1. Top of page
  2. Topological insulator nanostructures
  3. Recent progress in the understanding of exciton dynamics within phosphorescent OLEDs
  4. Real-time manipulation of ZnO nanowires on a flat surface employed for tribological measurements

L. M. Dorogin, S. Vlassov, B. Polyakov, M. Antsov, R. Lõhmus, I. Kink, and A. E. Romanov

Elastic and tribological properties of ZnO nanowires on Si wafer and highly oriented pyrolytic graphite (HOPG) are experimentally investigated and theoretically interpreted. Measurements are performed inside a scanning electron microscope (SEM) using real-time manipulation technique that enables two possible ways of data registration: “external” force registration with quartz tuning fork based sensor and “internal” force registration utilizing in situ observed elastic deformation of nanowires. It is possible to describe the complete range of tribological phenomena: static friction upon the transition to kinetic friction, pure kinetic friction and the relaxation of kinetic friction to self-balanced static friction.

Phys. Status Solidi B (2012) DOI 10.1002/pssb.201248445

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