Time-Dependent Density Functional Theory Modeling of Spin鈥揙rbit Coupling in Ruthenium and Osmium Solar Cell Sensitizers

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• 作者：Enrico Ronca ; Filippo De Angelis ; Simona Fantacci
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：July 31, 2014
• 年：2014
• 卷：118
• 期：30
• 页码：17067-17078
• 全文大小：529K
• ISSN：1932-7455

文摘

We report on the relevance of spin鈥搊rbit coupling on the optical properties of Ru(II)- and Os(II)-polypyridyl dyes effectively employed in dye-sensitized solar cells (DSCs). We include relativistic effects on time-dependent density functional theory calculations of selected complexes by using different levels of calculations, i.e., the scalar zero-order regular approximation (ZORA) and the fully relativistic ZORA including spin鈥搊rbit coupling, in such a way so as to disentangle and evaluate the spin鈥搊rbit effect. The widely investigated [M(bpy)₃]²⁺ (M = Ru(II) and Os(II)) have been selected as benchmark complexes in our calculations; this is followed by investigation of 鈥渞ealistic鈥?dyes used in DSCs, such as the prototypical N3 dye, its Os-based analogue, and a panchromatic Os(II) dye. We find that in Ru(II) complexes, spin鈥搊rbit coupling leads to a slight correction of the spectral shape, whereas only when we include the spin鈥搊rbit coupling we are able to reproduce the low-energy absorption bands characteristic of the Os(II) complexes. This study allows us to find a quantitative correlation between the strength of spin鈥搊rbit coupling and the metal center, highlighting the secondary effect of the different ligands experienced by the metal center.