Organic solar cells phthalocyanines

It is the purpose of this chapter to introduce photoinduced charge transfer phenomena in bulk heterojunction composites, i.e., blends of conjugated polymers and fullerenes. Phenomena found in other organic solar cells such as pristine fullerene cells [11,12], dye sensitised liquid electrolyte [13] or solid state polymer electrolyte cells [14], pure dye cells [15,16] or small molecule cells [17], mostly based on heterojunctions between phthalocyanines and perylenes [18] or other bilayer systems will not be discussed here, but in the corresponding chapters of this book. 

A similar temperature dependence of Isc, Voc, and r) is also reported for the lower mobility generation of solar cells, based on interpenetrating networks of conjugated polymers with fullerenes, but processed from solvents so that the initial efficiency is < 1% [156]. This behavior is discussed extensively in the section dealing with Isc. A positive temperature coefficient is also observed for the efficiency of Cgo single-crystal photoelectrochemical cells [160]. Finally, a temperature dependence of Isc qualitatively similar to that shown in Fig. 5.47a and 5.48 is also observed for organic solar cells based on Zn-phthalocyanine (ZnPc)/perylene (MPP) heterojunctions [161]. 

In organic solar cells consisting of zinc phthalocyanine and a perylene pigment it was possible to raise the short-eircuit eurrent by a factor of 1.5 when increasing the partial pressure of oxygen by a factor of three in comparison to that of ordinary atmosphere. The structure of a metal phthalocyanine complex is shown in Figure 1.15. 

Fig. 8.11 The early study on organic solar cell where active layer contains liquid crystalline phthalocyanine as p-type of semiconductor. This is not a BHJ active layer, but of p-i-n junction...

Figure 45 Formation of ruthenium phthalocyanine-based electron donor mateials for bulk heterojunction organic solar cells.

Sundarraj S, Bruder I, Hwang JH, Schoeneboom J, Koenemann M, Bahulayan S, Ojala A, Leow A, Wui Y, ErkP, Sens R, GessnerT (2012) Use of phthalocyanine compounds with aryl or hetaryl substituents in organic solar cells. US Patent 20120068123... 

Liu prepared a sandwich type coordination compound (103) from porphyrin and phthalocyanine with the assistance of a microwave. The resulted compounds showed good solubility in conventional organic solvents. The photoelectric conversion properties have been tested with a Gratzel type cell. The results revealed that the sandwich type compound showed better photo-electric conversion efficiency than the corresponding monomeric porphyrin or phthalocyanine precursors. The short-circuit photocurrent of the solar cell with this sandwich type compound as sensitizer, was, as high as 691.31 A cm-2, which was much better, than those of porphyrin or phthalocyanine monomers [100]. 

Uchida, S., Xue, J., Rand, B. R, and Forrest, S. R. 2004. Organic small molecule solar cells with a homogeneously mixed copper phthalocyanine C-60 active layer. Applied Physics Letters 84 (21) 4218 220. 

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