Solar cells panchromatic sensitizers

The optimal sensitizer for the dye-sensitized solar cell should be panchromatic, i.e., it should absorb visible light of all colors. Ideally, all photons at wavelengths shorter than a threshold of about 920 nm (see Section 9.16.1.1) should be harvested and converted to electric current.1,2 In addition, the sensitizer should fulfill several other demanding conditions ... 

Molecular engineering of ruthenium complexes that can act as panchromatic CT sensitizers for Ti02-based solar cells presents a challenging task as several requirements have to be fulfilled by the dye, which are very difficult to be met simultaneously. The lowest unoccupied molecular orbitals (LUMOs) and the highest occupied molecular orbitals (HOMOs) have to be maintained at levels where photo-induced electron transfer into the Ti02 conduction band and regeneration... 

Pechy P, Renouard T, Zakeeruddin SM et al (2001) Engineering of efficient panchromatic sensitizers for nanocrystalline Ti02-based solar cells. J Am Chem Soc 123 1613-1624 Zhu H, Wei J, Wang K et al (2009) Applications of carbon materials in photovoltaic solar cells. Solar Energy Mater Solar Cells 93 1461-1470... 

Molecular engineering of ruthenium complexes that can act as panchromatic charge-transfer sensitizers for TiOi-based solar cells presents a challenging task, as several requirements which are very difficult to be met simultaneously have... 

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. 

Nazeeruddin, M., et al. (2001). Engineering of efficient panchromatic sensitizers for nanocrystalline TiOj-based solar cells. /. Am. Chem. Soc. 123,1613-1624. 

Nazeeruddin M. K., Pechy P., Renouard T., Zakeeruddin S. M., Humphry-Baker R., Comte P., Liska P., Le Cevey, Costa E., Shklover V., Spiccia L., Deacon G. B., Bignozzi C. A. and Gratzel M. (2001), Engineering of efficient panchromatic sensitizers for nanocrystalline Ti02-based solar cells , J. Am. Chem. Soc. 123, 1613-1624. 

Scheme 34 Structural formula of trichromatic dye T and dichromatic dye D as well as their boradiazaindacene (BODIPY), ZnP, and squaraine (SQ) moieties. Adapted with permission from Waman J, Buchet F, Pellegrin Y, Blart E, Odobel F (2011) Panchromatic trichromophoric sensitizer for dye-sensitized solar cells using antenna effect. Org Lett 13(15) 3944-3947. Copyright (2011) American Chemical Society...

Waman J, Buchet F, Pellegrin Y et al (2011) Panchromatic trichromophoric sensitizer for dye-sensitized solar cells using antenna effect Org Lett 13(15) 3944-3947... 

Ball JM, Davis NKS, Wilkinson JD et al (2012) A panchromatic anthracene-fused porph3rtin sensitizer for dye-sensitized solar cells. RSC Adv 2(17) 6846-6853... 

Cid J-J, Yum J-H, Jang S-R, Nazeemddin MdK, Martinez-Ferrero E, Palomares E, Ko J, Gratzel M, Torres T (2007) Molecular cosensitization for efficient panchromatic dye-sensitized solar cells. Angew Chem Int Ed 46 8358-8362... 

Yum J-H, Baranoff E, Wenger S, Nazeeruddin MK, Gratzel M (2011) Panchromatic engineering for dye-sensitized solar cells. Energy Environ Sci 4(3) 842-857... 

As it is well known, calculations on the solar spectrum impinging on the Earth surface demonstrate that the ideal photosensitizer for a system that would absorb the maximum fraction of energy (somewhat above 1000 nm) would absorb near infrared photons, and of course, all of the photons above that limit. Thus, new sensitizers are continuously prepared with a maximum in the NIR for the use in solar cells. However, organic light absorbers have relatively narrow bandwidths separated by deep minima, which makes it difficult to obtain panchromatic absorption in a single organic semiconductor. 

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