Triplet antenna effect

Triplet Antenna Effect Poly(acetonaphthyl methacrylate)... 

HOLDEN AND SAFARZADEH-AMIRI Triplet Antenna Effect... 

Studies of Triplet Antenna Effect When copolymers of l-aceto-2-NMA with small amounts of 2,4-diaceto-l-NMA are excited at a wavelength where almost all of the light is absorbed by the first monomer the phosphorescence spectrum consists of contributions from both... 

Note that in the case where the Forster mechanism concerns an organic species transferring its energy to the lanthanide center to which it is bound, this is often referred to as the antenna effect and the ligand is sometimes called a sensitiser. Such an effect becomes efficient provided that the organic chromophore possesses a triplet excited state close to but at least 1700 cm-1 above that of the lanthanide emissive state (Parker and Williams, 1996). 

Fig. 8.3. FCS Proton exchange kinetics measurements at biological membranes, (a) Principal design of experiment. Liposomes were labeled with one FITC fluo-rophore undergoing fluorescence fluctuations due to protonation/deprotonation. (b) Collection of FCS curves of the vesicles at different pH. The FCS curves reflect singlet-triplet transitions in the microsecond time range, protonation kinetics in the 10-100 ps time range and translational diffusion in the milliseconds time range. Inset measured protonation relaxation rates vs. proton concentration, (c) Principle of the proton collecting antenna effect...

Figure 2.18 Schematic representation of photophysical processes in lanthanide(III) complexes (antenna effect). A = absorption, F = fluorescence, P = phosphorescence, L = lanthanide-centred luminescence, ISC = intersystem crossing, ET = energy transfer S = singlet, T = triplet. Full vertical lines radiative transitions dotted vertical lines nonradiative transitions...

Figure 1.10 Modified JablonskI diagram Illustrating the antenna effect. Abs - absorption, FI -fluorescence, Ph -phosphorescence, L - luminescence, ISC-intersystem crossing, ET - energy transfer, BT - back energy transfer, NR - non-radiative deactivation, - first excited singlet state, T - lowest excited triplet state, GS - ground state, f - emissive f excited state...

Ru(bpy)3+ complex placed into the inner cavity of the vesicle was used as such antenna . The lifetime of the triplet-excited state of this complex ( 0.6 ps) is sufficiently long, so that before its deactivation it can experience numerous collisions with the inner surface of the vesicle membrane and thus with the porphyrin molecules embedded into the membrane. Indeed, it was found that the introduction of Ru(bpy)2 + into the inner volume of the vesicle leads to the sixfold increase of the rate of the transmembrane PET [58, 61]. This effect results, first, from the spectral sensitization due to the light absorption by the ruthenium complex in the spectral region where porphyrin does not absorb, and, second, from the two-three fold increase of transfer from 3Ru(bpy)i+ to ZnTPPin. 

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