Photoluminescence properties of the

The nonlinear absorption of Ptn acetylide chromophores has also continued to retain the interest of many researchers. Malmstrom and coworkers have recently investigated Pt-acetylide chromophores blended with solid-state polymer matrices [94], An example of such a complex is 4.7. They found that the photoluminescence properties of the blends agreed well with that of dilute THF solutions containing the Pt-acetylides. Optical power limiting experiments showed that the clamping levels for dyes nonbonded to the polymer host were about half that for dyes in the highly cross-linked solids at similar concentrations. 

Tab. 6.1. Volumes of activation (in cm mol" ) calculated from pressure effects on the photoreaction/ photoluminescence properties of the Rh lll) complexes Rh(NH3)X + in various solvents (data taken from refs. [47] and [48]).

Possible mechanisms of an impurity effect on the photoluminescence properties of the Si02 nc-Si are summarized. The experimental data manifested the action of these mechanisms are presented. It is shown that, depending on the kind of the impurity, its concentration and annealing conditions, the enhancement or quenching of the photoluminescence associated with Si nanocrystals can be observed. 

In the final experiment to be presented h, we modified the oxide layer by HF attack and studied the effect of this treatment on the photoluminescence properties of the sample. The results are summarized in Fig. 5. We started fijom an already passivated sample whose PL spectrum is given by the black solid curve peaking at approximately 775 nm or 1.6 eV. Then the sample was... 

The electronic structure and photoluminescence properties of the dinuclear copper(I) complex [Cu2((i-Ph-NNN-Ph)2] (22) have also been reported [98]. X-ray crystal structure shows a short Cu-Cu separation of 2.45 A [99]. The complex is fluorescent at 77 K with a structured emission band at around 600 nm. The lowest lying excited state has been assigned to be 7C-7C /MLCT in nature. 

The BEuT thin films were prepared on STO (100) and STO (111) substrates by using chemical solution deposition, and the effects of Eu ion concentration and ciystallographic orientation on photoluminescent property of the thin films were investigated. The BEuT thin films prepared on STO (100) substrates grew with high c axis orientation due to very small... 

For copolymers of structure I, for both types of side-chains, there is a striking similarity with the optical properties of the corresponding models the absorption and photoluminescence maxima of the polymers arc only 0.08-0.09 eV red-shifted relative to those of the models, as shown in Figure 16-9 (left) for the octyloxy-substituted compounds. The small shift can be readily explained by the fact that in the copolymers the chromophorcs are actually substituted by silylene units, which have a weakly electron-donating character. The shifts between absorption and luminescence maxima are exactly the same for polymers and models and the width of the emission bands is almost identical. The quantum yields are only slightly reduced in the polymers. These results confirm that the active chro-mophores are the PPV-type blocks and that the silylene unit is an efficient re-conjugation interrupter. 

The primary goal of the researchers has been to produce Q-dots possessing all of the attributes of the Q-dots prepared using liquid-phase synthetic methods (that is adjustability of the nanocrystal identity and diameter and size monodispersity) and also the technological utility of Q-dots prepared by MBE (specifically, the deposition of nanocrystals with a defined orientation and an electrical output contact). It was shown that the E/C-synthesized 5-CuI and CdS Q-dots were indeed epitaxial with narrow size distribution and strong photoluminescence tunable by the particle size. Qne of the advantages of the E/C method is that it can be made size selective. The key point is that the size as well as the size dispersion of product nanoparticles are directed actually by the corresponding properties of the metal nanoparticles therefore the first deposition step assumes special importance. 

Poly(l,4-naphthylenevinylenes) have been prepared by metathesis polymerization of benzobarrelenes [181,182] and the photoluminescence properties of homopolymers and block-copolymers have been studied in some detail [183]. PPV also has been prepared via ROMP of [2.2]paracyclophane-l,9-diene [184] and ROMP of a paracyclophene that contains a solubilizing leaving group [185]. The resulting polymer is converted to PPV upon acid catalysis at room temperature. ADMET of 2,5-dialkyl-l,4-divinylbenzenes using Mo or W catalysts has... 

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. 

Various arylene dihalides and heteroarylene dihalides are applicable to the reaction of bisallene 163, and polymers 164 of various structures are available in good to excellent yields (M of 15 000-22000 with PDI of ca. 2.0). Photoluminescent and electroluminescent properties of the polymer 164 are also studied. 

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