Metadata of CSIR Papers
View Archive Info| Field | Value | |
| Creator |
Verma, S
Kar, P Das, A Palit, DK Ghosh, HN |
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| Subject |
Chemistry
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| Description |
We have synthesized ruthenium(II)- and osmium(II)-polypyridyl complexes ([M(bpy)(2)L](2+), in which M=Os(II) or Ru(II), bpy=2,2'-bipyridyl, and L=4-(2,2'-bipyridinyl-4-yl)benzene-1,2-diol) and studied the interfacial electron-transfer process on it TiO(2) nanoparticle surface using femtosecond transient-absorption spectroscopy. Ruthenium(II)- and osmium(II)-based dyes have a similar molecular structure; nevertheless, we have observed quite different interfacial electron-transfer dynamics (both forward and backward). In the case of the Ru(II)/TiO(2) system, single-exponential electron injection takes place from photoexcited nonthermalized metal-to-ligand charge transfer (MLCT) states. However, in the case of the Os(II/)TiO(2) system, electron injection takes place biexponentially from both nonthermalized and thermalized MLCT states (mainly 3 MLCT states). Larger spin-orbit coupling for the heavier transition-metal osmium, relative to that of ruthenium, accounts for the more efficient population of the (3)MLCT states in the Os(II)-based dye during the electron-injection process that yields biexponential dynamics. Our results tend to Suggest that appropriately designed Os(II)-polypyridyl dye can be a better sensitizer molecule relative to its Ru(II) analogue not only due to much broader absorption in the visible region of the solar-emission spectrum, but also oil account of slower charge recombination.
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| Publisher |
WILEY-V C H VERLAG GMBHWEINHEIMPO BOX 10 11 61, D-69451 WEINHEIM, GERMANY
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| Date |
2011-09-20T12:03:26Z
2011-09-20T12:03:26Z 2010 |
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| Type |
Article
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| Identifier |
CHEMISTRY-A EUROPEAN JOURNAL
0947-6539 http://hdl.handle.net/123456789/12333 |
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| Language |
English
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