Chemical Tuning and Absorption Properties of Iridium Photosensitizers for Photocatalytic Applications

Bokareva, Olga S.; Möhle, Tobias; Neubauer, Antje; Bokarev, Sergey I.; Lochbrunner, Stefan; Kühn, Oliver

doi:10.3390/inorganics5020023

Cited by 12 publications

(15 citation statements)

References 58 publications

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“…The first triplet-tuned functional, TT-ωPBEh, was constructed by an internal matching of E T from two DFT variants, ∆SCF and TDDFT. To evaluate the behavior of TT-ωPBEh, we compared its errors for Similar to conventional optimally tuned functionals, [247][248][249][250][251][252][253][254][255][256] we expected a broad application of our triplet tuning approach for π-conjugated organic molecules that were considered theoretically challenging before. Beyond the accurate predictions of spectroscopy and dynamics, the method can set the stage for the computationally aided design and screening of photoactive materials.…”

Section: Discussionmentioning

confidence: 99%

Triplet Tuning: A Novel Family of Non-Empirical Exchange–Correlation Functionals

Lin

Voorhis

2019

J. Chem. Theory Comput.

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In the framework of density functional theory (DFT), the lowest triplet excited state, T 1 , can be evaluated using multiple formulations, the most straightforward of which are unrestricted DFT (UDFT) and time-dependent DFT (TDDFT). Assuming the exact exchangecorrelation (XC) functional is applied, UDFT and TDDFT provide identical energies for T 1 (E T ), which is also a constraint that we require our XC functionals to obey. However, this condition is not satisfied by most of the popular XC functionals, leading to inaccurate predictions of low-lying, spectroscopically and photochemically important excited states, such as T 1 and the lowest singlet excited state (S 1 ). Inspired by the optimal tuning strategy for frontier orbital energies [T. Stein, L. Kronik, and R. Baer, J. Am. Chem. Soc. 131, 2818 (2009)], we proposed a novel and non-empirical prescription of constructing an XC functional in which the agreement between UDFT and TDDFT in E T is strictly enforced. Referred to as "triplet tuning", our procedure allows us to formulate the XC functional on a case-by-case basis using the molecular structure as the exclusive input, without fitting to any experimental data. The first triplet tuned XC functional, TT-ωPBEh, is formulated as a long-range-corrected (LRC) hybrid of Perdew-Burke-Ernzerhof (PBE) and Hartree-Fock (HF) functionals [M. A. Rohrdanz, K. M. Martins, and J. M. Herbert, J. Chem. Phys. 130, 054112 (2009)] and tested on four sets of large organic molecules. Compared to existing functionals, TT-ωPBEh manages to provide 1 arXiv:1806.00317v3 [physics.chem-ph] 15 Jan 2019more accurate predictions for key spectroscopic and photochemical observables, including but not limited to E T , the optical band gap (E S ), the singlet-triplet gap (∆E ST ), and the vertical ionization potential (I ⊥ ), as it adjusts the effective electron-hole interactions to arrive at the correct excitation energies. This promising triplet tuning scheme can be applied to a broad range of systems that were notorious in DFT for being extremely challenging.

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Section: Discussionmentioning

confidence: 99%

Triplet Tuning: A Novel Family of Non-Empirical Exchange–Correlation Functionals

Lin

Voorhis

2019

J. Chem. Theory Comput.

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“…In particular,t he approachw as also found useful for transition metal complexes. [45,[52][53][54] In this approach, elaborated below,t he range separation of the electronic repulsion term allows for an accurate descriptiono ft he asymptotic potential, whereas optimal choice of the range-separation parameter allowsf or an accurate determination of electronic and opticalp roperties, including the fundamental and opticalg ap. [43,51,55,56] Although originally developed primarily for applications in spectroscopy, it has been found to improve the description of some properties derived from total energy differences, such as the electric field gradient in CuCl, [57] bond length alternation in polyenes, [58] or deprotonation energieso fg as-phase amino acids.…”

Section: Introductionmentioning

confidence: 99%

Spin‐State Energetics of Fe Complexes from an Optimally Tuned Range‐Separated Hybrid Functional

Prokopiou

Kronik

2017

Chemistry A European J

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We assess the performance of the optimally tuned range-separated hybrid (OT-RSH) functional approach in predicting the ground-state electronic configuration and spin-state energetics of complexes that can potentially exhibit multiple spin configurations. To that end, we investigate eight iron complexes: four spin-crossover complexes, for which reference data from other approximate density functionals are available, and four smaller complexes, for which reference ab initio data are available. We show that the spin-state energetics are mostly governed by the percentage of short-range exact exchange and are only weakly influenced by the choice of the range-separation parameter. However, the electronic structure, especially the fundamental gap, is much more sensitive to the range-separation parameter. We further find that correct prediction of the ground state in spin-crossover compounds requires a reduction in the amount of short-range exact exchange, likely owing to a larger role of static correlation.

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“…Second, we also perform gas-phase calculations of the CuPc and CoPc anions with an OT-RSH functional [71,80,81,96], which uses a system-dependent but nonempirical tuning of the range-separation parameter and can produce highly accurate valence-electron spectra for molecules. In particular, the excellent performance of OT-RSH has been demonstrated for metal Pcs [80,81] and for other metallorganic complexes [71,97].…”

Section: Magnetic Configurations Of Gas-phase Cupc and Copcmentioning

confidence: 99%

Magnetic configurations of open-shell molecules on metals: The case of CuPc and CoPc on silver

Wruß

Prokopiou

Kronik

et al. 2019

Phys. Rev. Materials

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For nanostructured interfaces between open-shell molecules and metal surfaces that involve charge transfer upon adsorption, the investigation of molecular magnetic properties is an interesting yet difficult task, because in principle different magnetic configurations with distinct properties can be found. Here, we study the magnetic properties of CuPc-Ag and CoPc-Ag interfaces, which constitute interesting test cases because charge is transferred to the initially open-shell Pc molecules upon adsorption. Using hybrid density functional theory, we examine the stability of the various magnetic configurations occurring at these nanoscale interfaces, as well as for the corresponding gas-phase anions, and compare our findings to those of previous experimental studies. For CuPc-Ag, we identify a high-spin triplet configuration as the most likely configuration at the interface, whereas for CoPc-Ag a quenching of the total magnetic moment is found. Interestingly, such quenching is consistent with two distinctly different interfacial electronic configurations. These important differences in the magnetic properties of CuPc and CoPc on Ag are rationalized by variations in the interaction of their central metal atoms with the substrate. Our work facilitates a deeper understanding of the magnetic configuration and interlinked electronic-structure properties of molecule-metal interfaces. Furthermore, it highlights the necessity of an appropriate choice of methodology in tandem with a detailed evaluation of the different emerging magnetic properties.

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Chemical Tuning and Absorption Properties of Iridium Photosensitizers for Photocatalytic Applications

Cited by 12 publications

References 58 publications

Triplet Tuning: A Novel Family of Non-Empirical Exchange–Correlation Functionals

Triplet Tuning: A Novel Family of Non-Empirical Exchange–Correlation Functionals

Spin‐State Energetics of Fe Complexes from an Optimally Tuned Range‐Separated Hybrid Functional

Magnetic configurations of open-shell molecules on metals: The case of CuPc and CoPc on silver

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