Photo luminescence efficiencies

In conclusion, three-dimensional periodic nanostructures containing erbium ions have been fabricated based on artificial opal matrices. Their photo luminescence efficiency was found to be higher as compared to a reference glass sample. Possible reasons responsible for enhancement include enhanced excitation efficiency due to increase in efficient absorption length and modification of spontaneous decay of ions in a periodic lattice due to redistribution of photon density of states. 

Spin-orbit coupling will not strongly alter the mechanism of exciton formation in an organic matrix material, but it will have drastic effects on the efficiency of electro-luminescence in an OLED device. To illustrate this property, we will compare the efficiency which is obtainable with a purely organic molecule to the efficiency achievable with a transition metal complex, if both molecules exhibit equal photo-luminescence quantum yields. If one as-... 

Alternatively, undesirable side reactions may lead to persistent cation radicals. Due to these side reactions doping (p-type) of the organic semiconductor may occur, leading to a higher conductivity, but lower luminescence efficiency (photo and electroluminescence). However, by chemical or thermal (post-bake step at 180 °C) treatment, complete dedoping is possible and the luminescence efficiency is fully recovered. Additionally, in some cases the cation radical is able to attack the oxetane through nucleophilic reaction and ultimately start the same chain reaction as above [33]. 

The layer width is taken from the relation d > 1,5 dg, where dg - thickness of a gas discharge gap. The employment of a resistive layer instead of electrode profiling can significantly simplify the device manufacture. The UV radiation is efficiently converted into a visible one by a number of photo-luminophors, e.g. Zn2Si04 Mn. For stroboscopic registration of fast-proceeding processes the luminophors with short period of luminescence are used, e.g anthracene etc. 

MEH-PPV and P3MBET, were used. As a measure of the efficiency of the photo-induced charge transfer, the degree of luminescence quenching and the ratio of the charged photoexcitation bands to the neutral photoexcitation bands were taken. These two numbers are plotted in Figure 15-15 versus the electrochemical reduction potential. A maximum in the photoinduced electron transfer was determined for Cbo. 

Armelao L, Quici S, Barigelletti F, Accorsi G, Bottaro G, Cavazzini M, Tondello E (2010) Design of luminescent lanthanide complexes from molecules to highly efficient photo-emitting materials. Coord Chem Rev 254 487-505... 

The 1,2-dithienylethene unit has also been used to link together metal tris(bipyridyl) moieties including an unsymmetrical Ru(II)/Os(II) complex. In the open form luminescence from the MLCT state is observed with efficient energy transfer from ruthenium to osmium. However, the emission is quenched upon conversion to the closed form because of energy transfer to the photo-chromic 1,2-dithienylethene orbitals.55... 

Porphyrin is one of the most widely studied macrocyclic systems suitable for complexation with lanthanide(III) ions. Porphyrins can absorb strongly in the UV-vis region so as to serve as efficient photo-sensitizers, making lanthanide(III)porphyrinate complexes ideal candidates for luminescence imaging agents. Indirect excitation of porphyrin antenna chromopheres in close proximity to lanthanide ions can make the energy in the triplet state of the porphyrin ligand transfer efficiently to the excited state of the lanthanide ion so as to sensitize the lanthanide luminescence, particularly NIR emission. 

Other OTM compounds that are indicated by preliminary studies to be efficient triplet sensitizers include ClRe(C0)2L (Table 12). In dichloromethane at room temperature these complexes are strongly luminescent and photo-inert (41). Under the same conditions, the emissions are quenched by oxygen, anthracene, and trans-stilbene. The trans cis isomerization of trans-stilbene is efficiently sensitized by several of these species. Quantitative sensitization experiments indicated that the luminescing excited states of ClRe(C0)3L are produced with 100 percent... 

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