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Sayevich V.,TU Dresden | Gaponik N.,TU Dresden | Plotner M.,Institute of Semiconductors and Microsystems | Kruszynska M.,TU Dresden | And 7 more authors.
Chemistry of Materials | Year: 2015

Here, we present a ligand exchange of long insulating molecules with short, robust, and environmentally friendly iodide ions via a mild flocculation of PbSe nanocrystals (NCs). This ligand exchange leads to the formation of stable colloidal solutions in various polar solvents and in a broad concentration range via electrostatic repulsion. The iodide capping ligands preserve the electronic structure and maintain the optical properties of the PbSe NCs, both in solution and in the form of solid films. The spin-coated PbSe NC solids exhibit good transport characteristics with electron mobilities in the linear and saturation regimes reaching (2.1 ± 0.3) cm2/(V·s) and (2.9 ± 0.4) cm2/(V·s), respectively. This opens up opportunities for the low-cost and lowerature fabrication of NC thin films being attractive for applications in the fields of electronics and optoelectronics. © 2015 American Chemical Society. Source

Wang Y.,Nanyang Technological University | Leck K.S.,Nanyang Technological University | Van Ta D.,Nanyang Technological University | Chen R.,Nanyang Technological University | And 6 more authors.
Advanced Materials | Year: 2015

(Figure Presented) A blue (ca. 440 nm) whisper gallery mode laser in the liquid phase is realized by employing unconventional ternary CdZnS/ZnS alloyed-core/shell quantum dots. Detailed optical studies on page 169 by H. V. Demir, H. D. Sun, and coworkers indicate that such laser devices benefit from the high-quality-factor whispering gallery mode resonators and the novel gain media with minimal defects, suppressed Auger recombination, and large gain cross-section. © 2014 Wiley-VCH Verlag GmbH & Co. KGaA. Source

Lecaplain C.,CNRS Complex Interprofessional Research in Aerothermochemistry | Ortac B.,Fraunhofer Institute for Applied Solid State Physics | Ortac B.,UNAM Institute of Materials Science and Nanotechnology | Hideur A.,CNRS Complex Interprofessional Research in Aerothermochemistry | Limpert J.,Fraunhofer Institute for Applied Solid State Physics
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2010

We report on generation of high-energy pulses in a highly-normal dispersion fiber laser featuring large-mode-area microstructure fibers. Passive mode-locking is achieved using high modulation depth semiconductor saturable absorber mirror (SESAM). The total cavity dispersion is varied through insertion of a low-nonlinearity passive microstructure fiber inside the cavity. We study the effect of the cavity dispersion on the mode-locking performances. A systematic experimental and numerical description of the laser operation is addressed and the impact of the spectral filtering on the laser performances is discussed. © 2010 SPIE. Source

Yaman M.,UNAM Institute of Materials Science and Nanotechnology | Kondakci H.E.,UNAM Institute of Materials Science and Nanotechnology | Kondakci H.E.,Bilkent University | Bayindir M.,UNAM Institute of Materials Science and Nanotechnology | Bayindir M.,Bilkent University
Optics Express | Year: 2010

Te-enriched chalcogenide glass Ge15As25Se 15Te45 (GAST) is synthesized, thermo-optically characterized and used to fabricate a one dimensional photonic crystal cavity mode that is dynamically and reversibly tuned by temperature modulation. The optical cavity mode is designed using GAST and As2S3 glasses after fully determining their temperature dependence of the complex refractive indices in the visible and near infrared spectrum using spectroscopic ellipsometry. By making use of the very large thermo-optic coefficient (dn/dT = 4 × 10-4/°C) of GAST glass at 1.2 μm, the cavity mode of the multilayer was tuned reversibly more than 16 nm, which is, to the best of our knowledge, an order of magnitude larger for this kind of cavity modulation. Wide and dynamical spectral tuning of low bandgap chalcogenide glasses via temperature modulation can be utilized in photonic crystal based integrated optics, quantum dot resonance matching, solid state and gas laser components, and infrared photonic crystal fibers. © 2010 Optical Society of America. Source

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