Excitons dynamics

Bach FI, Renn A, Zumofen G and Wild U P 1999 Exciton dynamics probed by single molecule spectroscopy Phys. Rev. Lett. 82 2195-8... 

Higgins D A, Reid P J and Barbara P F 1996 Structure and exciton dynamics in J-aggregates studied by polarization-dependent near-field scanning optical microscopy J. Chem. Phys. 100 1174-80... 

S-S annihilation phenomena can be considered as a powerful tool for investigating tire exciton dynamics in molecular complexes [26]. However, in systems where tliat is not tire objective it can be a complication one would prefer to avoid. To tliis end, a measure of suitably conservative excitation conditions is to have tire parameter a< )T < 0.01. Here x is tire effective rate of intrinsic energy dissipation in tire ensemble if tire excitation is by CW light, and T = IS tire... 

Ohta, K., M. Yang, and G. R. Fleming. 2001. Ultrafast exciton dynamics of J-aggregates in room temperature solution studied by third-order nonlinear optical spectroscopy and numerical simulations based on exciton theory. J. Chem. Phys. 115 7609-7621. 

SV Frolov, M Liess, PA Lane, W Gellermann, ZY Yardeny, M Ozaki, and K Yoshino, Exciton dynamics in soluble poly(p-phenylene-vinylene) towards an ultrafast excitonic switch, Phys. Rev. Lett., 78 4285-4288, 1997. 

Lin H, Tabaei SR, Thomsson D, Mirzov O, Larsson P-O, Scheblykin IG (2008) Fluorescence blinking, exciton dynamics, and energy transfer domains in single conjugated polymer chains. J Am Chem Soc 130 7042-7051... 

An important question concerning energy trapping is whether its kinetics are limited substantially by (a) exciton diffusion from the antenna to RCs or (b) electron transfer reactions which occur within the RC itself. The former is known as the diffusion limited model while the latter is trap limited. For many years PSII was considered to be diffusion limited, due mainly to the extensive kinetic modelling studies of Butler and coworkers [232,233] in which this hypothesis was assumed. More recently this point of view has been strongly contested by Holzwarth and coworkers [230,234,235] who have convincingly analyzed the main open RC PSII fluorescence decay components (200-300 ps, 500-600 ps for PSII with outer plus inner antenna) in terms of exciton dynamics within a system of first order rate processes. A similar analysis has also been presented to explain the two PSII photovoltage rise components (300 ps, 500 ps)... 

This kinetics was additionally employed in Ref. [7] to discuss PIA exciton dynamics in cr-sexithienyl thin films in the ps regime. The data were fitted with (3k = 0.35, close to 1/3 and Tk = 6.5 ps. 

To summarize, the main conclusions we are able to draw from this investigation of the surface exciton dynamics, for our best crystals at T = 2 K,... 

Carrier and exciton dynamics in InGaN/GaN MQWs have also been studied at a high optical pumping power [34], At 7 K, a radiative decay lifetime of 250 ps was observed for the dominant transition at a generated carrier density of 1012/cm2. The time-resolved measurement showed that the decay of PL has a bimolecular recombination characteristic. At room temperature, the carrier recombination was found to be dominated by non-radiative processes with a measured lifetime of 130 ps. Well width dependence of carrier and exciton dynamics in InGaN/GaN MQWs has also been measured [35]. The dominant radiative recombination at room temperature was attributed to the band-to-band transition. Combined with an absolute internal quantum efficiency measurement, a lower limit of 4 x 10 9 cm3/s on the bimolecular radiative recombination coefficient B was obtained. At low temperatures, the carrier... 

Fidder H, Wiersma DA. Exciton dynamics in disordered molecular aggregates dispersive dephasing probed by photon echo and Rayleigh scattering. J Phys Chem 1993 97 11603-11610. 

Additional information related to the one- and two-exciton dynamics can be obtained from the 2D spectra, as will be shown in the following section. 

Another interesting example concerning exciton dynamics was also described by Kim and Weissman (83,84). They applied the transient magnetization technique to the study of the photoexcitation of phenazine doped with anthracene. In this system photo-excitation in the phenazine absorption region leads to a selectively populated phenazine triplet exciton which transfers the excitation to anthracene with conservation of polarization (27). The authors emphasized that the time dependence of the transient response requires further analysis, which must include an adequate quantum theoretical treatment on the evolution of the system shortly after excitation. One can expect that future refinement of this technique will lead to more exciting studies of the dynamics of triplet states and excitons in solid state. 

Can we increase the efficiency of exciton transport in amphi-PIC J-aggregates We have to take into consideration a large disorder degree observed in amphi-PIC J-aggregates that leads to different localization effects which influence exciton dynamics in amphi-PIC J-aggregates [5]. One of the... 

Keywords ASE Charge pairs Exciton dynamics Fluorescence lifetime Keto defects Phosphorescence Polyfluorene beta-phase... 

Some properties of the exciton dynamics of Mnp2 crystals have been elucidated through time-resolved studies of the emission at different parts of the exciton band after selective laser excitation jn some cases phase memory was found to be retained up to 1 /nsec but the details of the exciton dynamics require further knowledge of the exciton scattering mechanisms. 

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