Role of electronic localization in the phosphorescence of iridium sensitizing dyes

Himmetoḡlu, Burak; Marchenko, Alex; Dabo, Ismaïla; Cococcioni, Matteo

doi:10.1063/1.4757286

Cited by 33 publications

(38 citation statements)

References 109 publications

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“…∆SCF is gaining increasing popularity in the study of the excited states of both organic chromophores [41][42][43][44] and transition metal complexes. 45,46 This renewed interest is motivated in part by the growing demand for computationally cheap strategies for simulating with sufficient accuracy the excited-state structure and dynamics of large systems, for which high-level multireference methods are not yet a viable choice. The reliability of ∆SCF as applied to study the structure and dynamics of small molecules, organic dyes and even biological systems, has been assessed with respect to vibrational analysis, 47 exploration of PESs, 44,48 as well as dynamics in solution within QM/MM MD frameworks.…”

Section: Introductionmentioning

confidence: 99%

Solution Structure and Ultrafast Vibrational Relaxation of the PtPOP Complex Revealed by ΔSCF-QM/MM Direct Dynamics Simulations

et al. 2018

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Recent ultrafast experiments have unveiled the time scales of vibrational cooling and decoherence upon photoexcitation of the diplatinum complex [Pt2(P2O5H2)4]4– in solvents. Here, we contribute to the understanding of the structure and dynamics of the lowest lying singlet excited state of the model photocatalyst by performing potential energy surface calculations and Born–Oppenheimer molecular dynamics simulations in the gas phase and in water. Solvent effects were treated using a multiscale quantum mechanics/molecular mechanics approach. Fast sampling was achieved with a modified version of delta self-consistent field implemented in the grid-based projector-augmented wave density functional theory code. The known structural parameters and the PESs of the first singlet and triplet excited states are correctly reproduced. Besides, the simulations deliver clear evidence that pseudorotation of the ligands in the excited state leads to symmetry lowering of the Pt2P8 core. Coherence decay of Pt–Pt stretching vibrations in solution was found to be governed by vibrational cooling, which is in agreement with previous ultrafast experiments. We also show that the flow of excess Pt–Pt vibrational energy is first directed toward vibrational modes involving the ligands, with the solvent favoring intramolecular vibrational energy redistribution. The results are supported by thorough vibrational analysis in terms of generalized normal modes.

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Section: Introductionmentioning

confidence: 99%

Solution Structure and Ultrafast Vibrational Relaxation of the PtPOP Complex Revealed by ΔSCF-QM/MM Direct Dynamics Simulations

et al. 2018

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“…Notably, conventional DFT and TDDFT approximations tend to systematically destabilize occupied states and overstabilize unoccupied states in organic and organometallic complexes, leading in particular to the incorrect description of the electronic properties (charged excitations) and optical properties (neutral excitations) of donor-acceptor dyads, extended polymer molecules, and heavy-metal sensitizing dyes. [9][10][11][12] To overcome DFT limitations, one privileged route has been to resort to many-body approaches, namely, to many-body perturbation theory approximations such as GW. 13,14 The GW method, while accurate in predicting electronic spectra, is much more expensive than DFT although considerable progress has been achieved in reducing the cost of GW calculations.…”

Section: Introductionmentioning

confidence: 99%

Donor and acceptor levels of organic photovoltaic compounds from first principles

Dabo

Ferretti

Park

et al. 2013

Phys. Chem. Chem. Phys.

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Accurate and efficient approaches to predict the optical properties of organic semiconducting compounds could accelerate the search for efficient organic photovoltaic materials. Nevertheless, predicting the optical properties of organic semiconductors has been plagued by the inaccuracy or computational cost of conventional first-principles calculations. In this work, we demonstrate that orbital-dependent density-functional theory based upon Koopmans' condition [Phys. Rev. B 82, 115121 (2010)] is apt at describing donor and acceptor levels for a wide variety of organic molecules, clusters, and oligomers within a few tenths of an electron-volt relative to experiment, which is comparable to the predictive performance of many-body perturbation theory methods at a fraction of the computational cost.

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“…If the system does not show magnetization and the ground state is a Singlet state, Singlet excitations can also be calculated to a reasonable approximation without taking spin explicitly into account. This has been shown for the case of gas phase Azobenzene [37], O 2 on Al( 111) [29] and recently also for Iridium complexes [40], the latter work also providing a rationalization for the success of this approach.…”

Section: ∆Self-consistent-field-dft and Le∆scf-dftmentioning

confidence: 54%

Excited-state potential-energy surfaces of metal-adsorbed organic molecules from linear expansion Δ-self-consistent field density-functional theory (ΔSCF-DFT)

Maurer

Reuter

2013

The Journal of Chemical Physics

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Accurate and efficient simulation of excited state properties is an important and much aspired cornerstone in the study of adsorbate dynamics on metal surfaces. To this end, the recently proposed linear expansion Δ-self-consistent field method by Gavnholt et al. [Phys. Rev. B 78, 075441 (2008)] presents an efficient alternative to time consuming quasi-particle calculations. In this method, the standard Kohn-Sham equations of density-functional theory are solved with the constraint of a non-equilibrium occupation in a region of Hilbert-space resembling gas-phase orbitals of the adsorbate. In this work, we discuss the applicability of this method for the excited-state dynamics of metal-surface mounted organic adsorbates, specifically in the context of molecular switching. We present necessary advancements to allow for a consistent quality description of excited-state potential-energy surfaces (PESs), and illustrate the concept with the application to Azobenzene adsorbed on Ag(111) and Au(111) surfaces. We find that the explicit inclusion of substrate electronic states modifies the topologies of intra-molecular excited-state PESs of the molecule due to image charge and hybridization effects. While the molecule in gas phase shows a clear energetic separation of resonances that induce isomerization and backreaction, the surface-adsorbed molecule does not. The concomitant possibly simultaneous induction of both processes would lead to a significantly reduced switching efficiency of such a mechanism.

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Role of electronic localization in the phosphorescence of iridium sensitizing dyes

Cited by 33 publications

References 109 publications

Solution Structure and Ultrafast Vibrational Relaxation of the PtPOP Complex Revealed by ΔSCF-QM/MM Direct Dynamics Simulations

Solution Structure and Ultrafast Vibrational Relaxation of the PtPOP Complex Revealed by ΔSCF-QM/MM Direct Dynamics Simulations

Donor and acceptor levels of organic photovoltaic compounds from first principles

Excited-state potential-energy surfaces of metal-adsorbed organic molecules from linear expansion Δ-self-consistent field density-functional theory (ΔSCF-DFT)

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