Perylene conversion

Production of a two-layer film made out of copper phthalocyanine and a perylene tetracarboxylic derivative. A power conversion efficiency of about 1% has been achieved. 

Fujino, T, and Tahara, T. 2003. femtosecond fluorescence up-conversion microscopy Excitation dynamics in ct-perylene microcrystal. J. Phys. Chem. B 107 5120. 

Fig. 1. The CCD camera image of the a-perylene microcrystal used for the femtosecond fluorescence up-conversion microscopy...

An alternative theory associates electron transfer with transfer of a state of aromaticity from molecule to molecule within the stack (77AG(E)519). Efficient charge transport was identified with conversion of a neutral, antiaromatic system to a charged, aromatic radical by electron transfer. This interpretation has been eroded by the synthesis of conductors from aromatic systems such as perylene hexafluoroarsenate (81MI11301) or polypyrrole tetrafluoroborate (80CC397, 81MI11300) where an electron is transferred from a neutral, aromatic molecule to a non-aromatic charged radical. 

Gregg et at.si) examined photosensitization of perylene pigments (Dye 15-17) on a porous Sn02 thin film instead of Ti02 film as DSC, in view of energy matching with conduction band of semiconductors and LUMO of the sensitizers. When perylene-3,4-dicarboxylic acid-9,10-(5-phenanthroline) carboximide (Dye 15) was used, Jsc of 3.26 mA-cm 2, of 0.45 V, and a photoelectric conversion efficiency of 0.89% were observed under AM 1.5 irradiation. IPCE achieves close to 40% at 460 nm. 

A palladium-platinum-charcoal catalyst appears to be particularly effective for the dehydrogenative coupling of two benzene rings with formation of a third such ring, as in the conversion of o-terphenyl (8) to triphenylene (9), and of 1,1 -dinaphthyl (10) to perylene (II). The catalyst is prepared by adding 400 g. of granular... 

Compound Id behaves similarly, but the overall conversion efficiency is significantly lower, i. e. 0.022%. As a result, although no itt-conjugation between the perylene dye and the tin dioxide nanoparticles exists, electron transfer actually occurs, probably through a bridge-assisted mechanism as previously proposed for dye-excited states weakly coupled to semi-conducting particles. o On the basis of this mechanism, the lower cell efficiency found for Id-modified electrodes could be due to the longer hexylene linker in... 

Figure 6. Rate of conversion of perylene to endoperoxide as estimated from decrease in fluorescence intensity at 450 nm.

As shown in Figure 6 the rate appears to be first order, up to relatively high degrees of conversion, and is several orders of magnitude faster than in the absence of the polymer electrolyte. After the perylene has been reacted in this way it can be removed from the aqueous solution by extraction with ether, more perylene can then be added, and the reaction continued. 

Coumarin 2 has been paired as a donor with a diamino-substituted per-ylene near-IR emitter to produce a FRET-based UV to NIR frequency converter (Scheme 31) [92]. Excitation at the coumarin 2 A,max ( ex = 345 nm) resulted in FRET to the higher excited state (S ) of the perylene core. This state imdergoes rapid internal conversion to the first excited singlet state (Si, Kasha s rule), from which emission is observed. Comparison of the integrated donor emission in the absence of the core and in the target dendrimer indicated a 99% energy transfer efficiency, accompanied by a 6.2-fold increase in the core emission relative to the emission in the absence of peripheral donors. 

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