A-sexithiophene

Analysis of the spin-1/2 2-PADMR spectrum is more complicated as it contains two features with increased and decreased transmission. As the photoexcitation density is proportional to -AT, we describe these as PA-quenching (Sn<0) and PA-enhancing (Sn >0) bands. We defer detailed discussion of the spectrum to the following section, where we compare the doping, PA, and PADMR studies of a-sexithiophene (u-6T) and polythiophene. Magnetic resonance is found to enhance... 

The theory predicts a strong dependence of photogeneration efficiencies on the field and it approaches unity at high field. The temperature sensitivity decreases with the increase in field. The theory has found satisfactory explanations in the photogeneration process in many organic disordered systems, such as PVK (Scheme la) [25], and triphenylamine doped in polycarbonate [26], Figure 4 shows an example of the field dependence of c() calculated from Eq. (22) (the solid lines) to fit the quantum efficiency data at room temperature for hole and electron generation in an amorphous material. The material consists of a sexithiophene covalently linked with a methine dye molecule (compound 1) (Scheme 2). 

This work was partially supported by NATO (Grant No PST.CLG.979685). Fig. 4 and Figs. 6-7 are reprinted with permission from Elsevier from Synthetic Metals, 109, Jursenas et al., Femtosecond excited-state dynamics in N,N-dimethylaminobenzylidene-l,3-indandione DMABI films, p. 171, 2000, and from Chemical Physics Letters, 320, G. Klein, Transient femtosecond spectroscopy in a-sexithiophene single crystals, p. 67, 2000, respectively. 

A particularly interesting fact is that in the case of a-sexithiophene, or a6T, work on prototype devices such as MISFETs has shown that thin films of a6T molecules actually exhibit better performance characteristics than the corresponding polymer, polythiophene, and rival those of amorphous silicon41. a6T also has been used in light emitting diodes42-44. 

The adsorption-induced perturbation of electrical potential in an organic semiconductor has been assessed experimentally by photoelectron spectroscopy [43]. Binding methanol to the nonpolar organic semiconductor film a-sexithiophene... 

A novel approach to a sexithiophene relying on metalation of the terthiophene 30 has been reported, wherein treatment of its lithio-derivative with dppfPtCL gave the complex 31, which could in turn be converted to the target molecule 32 by an oxidative homocoupling... 

Additional studies have been devoted to oligothiophenes with electron-deficient fluorene-based groups <07JMA1055>, and a sexithiophene incorporating two fused TTF moieties... 

Horowitz, G. et al.. Field-effect transistor made with a sexithiophene single crystal,... 

Fig. 36. Energy level diagram of the l Ba exciton band structure of a-sexithiophene (adapted from [142a]). Copyright 1998, American Institute of Physics.

Y. Sakamoto, S. Komatsu and T. Suzuki, Properties and crystal structure of perfluoro-a-sexithiophene, Synth. Met., 133-134, 361-363 (2003). 

Conjugated a-sexithiophenes show differences in electrochemical behavior, although the electronic inductive effects of these substituents are comparable. Long alkyl or oxyalkyl side chains lead to an enhancement of electrochemical reversibility and stabilization of the cation radical state [501]. 

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