P216
On the Role of Electronic Structure of Ruthenium polypyridyl Dyes in the Photoconversion Efficiency of Dye Sensitized solar cells: A Semi-Empirical Investigation.
K. Srikanth, V. R. Marathe and Manoj K. Mishra,
Tetsuo Soga(*) and M. Umeno(*)
Indian Institute of Technology,
(*)Nagoya Institute of Technology
ZINDO/1 calculations on cis - (X)2 - bis[4,4'-dicarboxy-2,2'-bipyridine] Ru(II) and cis - (X)2 - bis [5,5'-dicarboxy-2,2'-bipyridine] Ru(II) complexes were done, where X = Cl-, CN- and NCS- to provide an unifying correlation between the electronic structure of these complexes and the photoconversion efficiency using it as a sensitizer for the nanocrystalline TiO2 based solar cells in terms of the relative position of HOMO and LUMO orbital energies of the dye with respect to the valence and conduction band energy levels of the anatase TiO2. Our results indicate that the earlier notions about the LUMO profile and its position vis-a-vis the conduction band of the anatase TiO2 determining the photoconversion efficiency of these cells are simplistic and that the HOMO-LUMO transition may involve a cluster of unoccupied orbitals and not just the LUMO. The state level description including CI offers a better correlation with the spectral and electrochemical properties!
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