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Electronic structure and optical properties of isolated and TiO 2 ‐grafted free base porphyrins for water oxidation: A challenging test case for DFT and TD‐DFT
Author(s) -
Daoudi Syrine,
Semmeq Abderrahmane,
Badawi Michael,
Assfeld Xavier,
Arfaoui Youssef,
Pastore Mariachiara
Publication year - 2019
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.26027
Subject(s) - density functional theory , excitation , chemistry , atomic orbital , range (aeronautics) , conduction band , hybrid functional , free base , base (topology) , atomic physics , molecular physics , computational chemistry , electron , materials science , physics , salt (chemistry) , mathematics , quantum mechanics , composite material , mathematical analysis
Seven free base porphyrins employed in dye‐sensitized photoelectrosynthetic cells are investigated with the aim of benchmarking the ability of different density functional theory (DFT) and time‐dependent DFT approaches in reproducing their structure, vertical, and E 0‐0 excitation energies and the energy levels alignment (red‐ox properties) at the interface with the TiO 2 . We find that both vertical and E 0‐0 excitation energies are accurately reproduced by range‐separated functionals, among which the ω B97X‐D delivers the lowest absolute deviations from experiments. When the dye/TiO 2 interface is modeled, the physical interfacial energetics is only obtained when the B3LYP functional is employed; on the other hand, M06‐2X (54% of exchange) and the two long‐range corrected approaches tested (CAM‐B3LYP and ω B97X‐D) excessively destabilize the semiconductor conduction band levels with respect to the dye's lowest unoccupied molecular orbitals (LUMOs), predicting no pathway for electron injection. © 2019 Wiley Periodicals, Inc.