Photoluminescence dynamics

Martini IB, Smith AD, Schwartz BJ (2004) Exciton-exciton annihilation and the production of interchain species in conjugated polymer films Comparing the ultrafast stimulated emission and photoluminescence dynamics of MEH-PPV. Phys Rev B 69(3)... 

L. Bergman, X. B. Chen, J. L. Morrison, J. Huso, and A. P. Purdy, Photoluminescence dynamics in ensembles of wide-band-gap nanocrystallites and powders, J. Appl. Phys. 96, 675-682 (2004). 

Figure 7.4 Sequence of 100 fs frames selected from a stroboscopic fluorescence movie of several simultaneously excited CdS (Sei < nanobelts. The dark-field image of the same group is shown in the last frame (bottom right). The red circles highlight the distinct photoluminescence dynamics of individual nanobelts.

Figure 7.6 Schematic representation of three dominant decay channels responsible for the complex photoluminescence dynamics of the CdSxSei, t nanobelts. The set of the corresponding rate reactions which were used to model the observed dynamics is shown below the diagram.

Figure 21.6 Schematic illustration of the dynamics of the photoluminescence from the Au(0) i system. The inset shows the comparison of the Au(0) i surface plasmon absorption peak with the spectral distribution of the Au(0) i emission peakfor excitation at 3.14 eV (395 nm).

Luminescence, in particular photoluminescence, constitutes a well-established discipline in analytical science where the cited hallmarks include remarkable sensitivity, wide dynamic range and low detection limits (-10under suitable conditions). These collective merits are often umivaled by other optical techniques, and hence its wide adoption in the life sciences for determining trace constituents in biological and environmental samples. Moreover, its fast response, high spatial resolution and remote sensing capabilities make it attractive for real-time analytical problems such as process manufacturing (process analysis or PAT) and field applications. ... 

Spectroscopic properties of [Ru(bpy)3] " ", and the effects of varying the diimine ligands in [Ru(bpy)3 L ] + (L = diimine) on the electronic spectra and redox properties of these complexes have been reviewed. The properties of the optical emission and excitation spectra of [Ru(bpy)3] +, [Ru(bpy)2(bpy-d )] + and [Ru(bpy-d )3] " " and of related Os, Rh , and Pt and Os species have been analyzed and trends arising from changes in the metal d or MLCT character in the lowest triplet states have been discussed. A study of the interligand electron transfer and transition state dynamics in [Ru(bpy)3] " " has been carried out. The results of X-ray excited optical luminescence and XANES studies on a fine powder film of [Ru(bpy)3][C104]2 show that C and Ru localized excitation enhances the photoluminescence yield, but that of N does not. 

Polymer nanotubes composites are now extensively studied. Indeed, one may associate the properties of the polymer with those of nanotubes. This is the case of the mechanical reinforcement of standard polymer for example, but also one can take advantage of the specific electronic properties of the nanotubes. Therefore, we prepared composites with either saturated polymers like polymethylmethacrylate and MWNTs [27]. The electrical conductivity of these compounds as a function of the nanotube content exhibits for example a very low percolation threshold, (a few % in mass) and therefore they can be used as conducting and transparent layers in electronic devices such as Light Emitting Diodes (LEDs). Another type of composite that we have studied is based on the use of a conjugated polymer, polyphenylene-vinylene (PPV) known for its photoluminescence properties and SWNTs. We prepared this composite by mixing SWNTs to the precursor polymer of PPV. The conversion into PPV was subsequently performed by a thermal treatment at 300°C under dynamical vacuum [28],... 

In the present paper, we report on the dynamics of He filling the fullerite C6o fee lattice octahedral and tetrahedral interstitial voids with the respective sizes of 4.12 and 2.26 A [2], both larger than the helium Van der Waals diameter of 2.14 A [3], We also present results of study of influence of He intercalation on of photoluminescence spectra of Ceo single crystal in the low temperature phase. The measurement technique as well as the experimental setup for structural [4-6] and luminescent [5, 6] studies have been reported elsewhere. 

Figure 19.19 Left side Variation of the photoluminescence intensity E (b) of the PEG-functionalized Au and CdTe nanoparticles depending on the temperature (a) (c) shows the calculated photon-field enhancement factor P of the CdTe nanoparticles as a function of time. Right side Schematic representation of a dynamic nanothermometer based on a nanoparticle superstructure. This superstructure consists of two types of nanoparticles (gold and CdTe) connected by polymeric spacers.118 (Reprinted with permission from J. Lee et al., Angew. Chem. Int. Ed., 2005, 44, 7439-7442. Copyright Wiley-VCH Verlag GmbH Co. KGaA.)...

Studies on luminescence of CdS colloids provide useful knowledge on the energy and nature of recombination sites of charge carriers in the colloidal particles. The regularities of the colloid photoluminescence quenching provide the information on the dynamics of electrons and holes in semiconductor particles as well as on the kinetics of interfacial electron transfer. Of a particular interest are studies on the luminescence of colloidal solutions of the so-called Q-semiconductors, their properties depending on the size of semiconductor particles due to the quantum size effects. 

Rajh, T. Micic, O. I. Lawless, D. Serpone, N. Semiconductor photophysics. 7. Photoluminescence and picosecondcharge carrier dynamics in CdS quantum dots confined in a silicate glass, J. Phys. Chem. 1992, 96, 4633. 

This review deals with the applications of photolurainescence techniques to the study of solid surfaces in relation to their properties in adsorption, catalysis, and photocatalysis, After a short introduction, the review presents the basic principles of photolumines-cence spectrosajpy in relation to the definitions of fluorescence and phosphorescence. Next, we discuss the practical aspects of static and dynamic photoluminescence with emphasis on the spectral parameters used to identify the photoluminescent sites. In Section IV, which is the core of the review, we discuss the identification of the surface sites and the following coordination chemistry of ions at the surface of alkaline-earth and zirconium oxides, energy and electron transfer processes, photoluminesccncc and local structure of grafted vanadium oxide, and photoluniinescence of various oxide-... 

Dynamics of photoluiiiinesceiice refers to the behavior of photoluminescence in the presence of reactant molecules as the pressures of reactant molecules and/or diffusion rates are changed. It is possible to obtain detailed information about the excited state of the emitting sites as a function of time during their transient lifetimes. 

This review covers adsorption, catalysis, and photocatalysis that can be investigated and understood by photoluminescence spectroscopy. Most of the results discussed in this review have been obtained by photoluminescence techniques, but other, complementary techniques, are also discussed to emphasize the originality and potential value of photoluminescence spectroscopy, particularly with regard to anion coordination chemistry, excited states, and reaction dynamics. The latter field is of utmost importance in chemistry (35). Additional applications of photoluminescence spectroscopy to the study of solid surfaces are reviewed in the books Photochemistry on Solid Surfaces"(. 6) and Surface Photochemistry (37). 

The results obtained from such dynamic photoluminescence studies shown in Fig. 41, together with the results obtained for O2 and CO. permit calculation of the absolute rate constants of quenching for the various molecules, as follows 9.34 x 10 for O2, 3.52 x 10 for C2H4, 2.24 x 10 for rram -2-butene, and 1.51 x 10 for N2O, all in units of (g/mol s), respectively (33,34,56,69,115-117). Consequently, the reactivities of these molecules toward the charge-transfer excited state of the vanadyl species decrease in the order O2 > CO > C2H4 > CsHg > trans-l-C Wg > N2O (120, 208-210). 

Anpo and Che write about applications of photoluminescence techniques, which are powerful but only seldom used methods for the identification of surface sites and their local environments, particularly on oxide surfaces. The dynamics of energy and electron transfer processes are discussed in light of catalytic and photocatalytic phenomena. 

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