Luminescence chromophores

In contrast to organic chromophores, luminescent lanthanide complexes are believed to be promising candidates to solve this problem. The spectroscopic properties of some lanthanide ions are ideal for use in full color displays, as is known from inorganic luminescent materials in cathode-ray and projection television tubes. Luminescent lanthanide complexes belong to a special class of emitters, exhibiting the following important advantages. 

Mason M D, Credo G M, Weston K D and Buratto S K 1998 Luminescence of individual porous Si chromophores Phys. Rev. Lett. 80 5405-8... 

We have studied two types of polymers that both belong to the second case those in which luminescent chromophores (typically K-coujugatcd oligomers) are separated by higher-energy-gap blocks (see Fig. 16-1 a) and those in which the chromophores are linked to each other in a non-coplanar way (sec Fig. 16-lb). 

Electron-Deficient Polymers - Luminescent Transport Layers 16 Other Electron-Deficient PPV Derivatives 19 Electron-Deficient Aromatic Systems 19 Full Color Displays - The Search for Blue Emitters 21 Isolated Chromophores - Towards Blue Emission 21 Comb Polymers with Chromophores on the Side-Chain 22 Chiral PPV - Polarized Emission 23 Poly(thienylene vinylene)s —... 

Fig. 4.1.3 Absorption spectra of aequorin (A), spent solution of aequorin after Ca2+-triggered luminescence (B), and the chromophore of aequorin (C). Fluorescence emission spectrum of the spent solution of aequorin after Ca2+-triggered bioluminescence, excited at 340 nm (D). Luminescence spectrum of aequorin triggered with Ca2+ (E). Curve C is a differential spectrum between aequorin and the protein residue (Shimomura et al., 1974b) protein concentration 0.5 mg/ml for A and B, 1.0 mg/ml for C. From Shimomura and Johnson, 1976.

The light emitter in Latia luminescence. The purple protein is strongly fluorescent in red. Thus, at first glance, it would appear to be a most probable candidate for the light emitter or its precursor. However, this possibility was ruled out when we found that there is no way to relate the fluorescence of the purple protein to the bioluminescence spectrum. Thus, the luciferase must contain a chromophore that produces the light emitter. 

The photoprotein is non-fluorescent. The absorption spectrum of purified photoprotein shows a very small peak at 410 nm, in addition to the protein peak at 280 nm (Fig. 10.2.5). The peak height at 410 nm appears to be proportional to the luminescence activity of the protein. The protein also shows extremely weak absorption peaks at about 497, 550 and 587nm (not shown). These absorption peaks, except the 280 nm peak, might be due to the presence of a chromophore that is functional in the light emission. 

Luminescence lifetimes are measured by analyzing the rate of emission decay after pulsed excitation or by analyzing the phase shift and demodulation of emission from chromophores excited by an amplitude-modulated light source. Improvements in this type of instrumentation now allow luminescence lifetimes to be routinely measured accurately to nanosecond resolution, and there are increasing reports of picosecond resolution. In addition, several individual lifetimes can be resolved from a mixture of chromophores, allowing identification of different components that might have almost identical absorption and emission features. 

Dendrimer 1 + is a classical example of a dendrimer containing a luminescent metal complex core. In this dendrimer the 2,2 -bipyridine (bpy) ligands of the [Ru(bpy)3] +-type core carry branches containing 1,2-dimethoxybenzene- and 2-naphthyl-type chromophoric units [15]. 

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