Search results for "Blues"
showing 5 items of 65 documents
From linear quaterthiophene to sulflower: A comparative theoretical study
2009
Abstract In this paper, we report a theoretical study of four types of thiophene-based oligomers showing the same number of C C double bonds and very different molecular structures. The comparative study has been performed on the basis of B3LYP/6-31G∗∗ calculations. The way the thiophene rings are linked together has a remarkable influence on the molecular and electronic properties. Linear quaterthiophene and heptathienoacene show similar aromatic structures but a loss of π-conjugation is detected for the latter due to the condensation of thiophene rings. A blue shift of the most intense electronic transition is predicted for fused heptathienoacene compared with non-fused quaterthiophene. C…
Low-dimensional iodide perovskite nanocrystals enable efficient red emission
2019
We report herein a simple ligand-assisted reprecipitation method at room temperature to synthesize mixed-cation hybrid organic–inorganic perovskite nanocrystals with low structural dimensionality.
Two‐Dimensional Electron Gas Effects on the Photoluminescence from a Nonintentionally Doped AlGaN/GaN Heterojunction
2002
Photoluminescence measurements on an AlGaN/GaN single heterojunction (SH), where piezoelectric and spontaneous polarization effects confine a two-dimensional electron gas (2DEG), are presented. Well-defined emissions between the bulk excitonic transitions and their LO-phonon replica are attributed to spatially indirect excitons located close to the interface. The strong interfacial electric field separates photogenerated holes and electrons, weakening their Coulomb interaction and causing a blueshift with increasing excitation intensity due to carrier population effects. In addition, direct experimental proof is obtained by applying an electric field normal to the interface. An energy shift…
Spectral dynamics of incoherent waves with a noninstantaneous nonlinear response
2013
We study the influence of a constant background noise on the dynamics of spectral incoherent solitons, which are incoherent structures sustained by a noninstantaneous (Raman-like) nonlinearity. As the level of the noise background increases, the incoherent wave enters a novel nonlinear regime characterized by oscillatory dynamics of the incoherent spectrum, which develop within a spectral cone during the propagation. In contrast to the conventional Raman-like spectral red shift, such incoherent spectral dynamics can be characterized by a significant spectral blue shift. On the basis of the kinetic wave theory, we derive explicit analytical expressions of these incoherent oscillatory spectra…