Solar cells heterojunctions

Basol BM (1984) High-efficiency electroplated heterojunction solar cell. J Appl Phys 55 601-603... 

Dennler, G. Scharber, M. C. Brabec, C. ]., Polymer-fullerene bulk-heterojunction solar cells. Adv. Mater. 2009, 21,1323-1338. 

Blom PWM, Mihailetchi VD, Koster LJA, Markov DE (2007) Device physics of polymer fullerene bulk heterojunction solar cells. Adv Mater 19 1551 Onsager L (1938) Initial recombination of ions. Phys Rev 54 554... 

Limpinsel M, Wagenpfahl A, Mingebach M, Deibel C, Dyakonov V (2010) Photocurrent in bulk heterojunction solar cells. Phys Rev B 81 085203... 

Cuiffi J, Benanti T, Nam WJ, Fonash S (2010) Modeling of bulk and bilayer organic heterojunction solar cells. Appl Phys Lett 96 143307... 

Scharber MC, Wuhlbacher D, Koppe M, Denk P, Waldauf C, Heeger AJ, Brabec CL (2006) Design rules for donors in bulk-heterojunction solar cells - towards 10% energy-conversion efficiency. Adv Mater 18 789... 

The incorporation of siloles in polymers is of interest and importance in chemistry and functionalities. Some optoelectronic properties, impossible to obtain in silole small molecules, may be realized with silole-containing polymers (SCPs). The first synthesis of SCPs was reported in 1992.21 Since then, different types of SCPs, such as main chain type 7r-conjugated SCPs catenated through the aromatic carbon of a silole, main chain type cr-conjugated SCPs catenated through the silicon atom of a silole, SCPs with silole pendants, and hyperbranched or dendritic SCPs (Fig. 2), have been synthesized.10 In this chapter, the functionalities of SCPs, such as band gap, photoluminescence, electroluminescence, bulk-heterojunction solar cells, field effect transistors, aggregation-induced emission, chemosensors, conductivity, and optical limiting, are summarized. 

A series of ruthenium(II) phthalocyanines with one or two pyridyl dendritic olig-othiophene axial substituent(s) have also been reported (compounds 50 and 51) [50], The dendritic ligands absorb in the region from 380 to 550 nm, which complements the absorptions of the phthalocyanine core. This combination results in better light harvesting property and enhancement in efficiency of the corresponding solar cells. The solution-processed photovoltaic devices made with these compounds and fullerene acceptor give efficiencies of up to 1.6%. These represent the most efficient phthalocyanine-based bulk heterojunction solar cells reported so far. 

Both phthalocyanines and squaraines are good candidates for bulk heterojunction solar cells. Recently, a supramolecular hetero-array of these functional dyes Pc-Sq-Pc (compound 52) has been reported for the first time, which exhibits a large coverage of the solar spectrum from 250 to 850 nm [51]. This axially held assembly serves as a robust panchromatic sensitizer. Upon excitation, it forms the radical ion pair Pc+-Sq -Pc with a long lifetime of 24 2 p,s. The use of this assembly as a donor material in solution processable bulk heterojunction solar cells has also been briefly studied. 

Although ZnO has also been applied in so-called amorphous/crystalline heterojunction solar cells consisting of a (doped) silicon wafer and thin doped a-Si H layers to build the p-n junction, we will restrict ourselves here to solar cells and modules with amorphous and/or microcrystalline absorber layers, i.e., real thin film silicon solar cells. For detailed information on the use of ZnO in crystalline silicon wafer based devices, the reader is referred to the literature (see e.g. [23,24]). 

Semiconductor Aspects of Organic Bulk Heterojunction Solar Cells 161... 

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