DFT predictions of the oxidation potential of organic dyes for opto-electronic devices

Capobianco, Amedeo; Velardo, Amalia; Peluso, Andrea

doi:10.1016/j.comptc.2015.07.023

Cited by 12 publications

(7 citation statements)

References 76 publications

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“…With 50% HFX, which corresponds to the BHHLYP functional, the best prediction for E 0 could be achieved, with an MSD of ∼−0.1 V. It is known that the optimal amount of HFX for E 0 estimation differs for individual chemicals, and for these systems, it was in the range of 50%. Failure of the functional with zero percentage of HFX (generalized gradient approximation, GGA), which gives the largest underestimation, is noted, and similar observations for oxidation potential estimation have been reported by other groups. ,, For E * ,Δ computation, we observed that the more HFX that the functional includes, the poorer its performance. This is related to an overestimation of fluorescence energy.…”

Section: Resultssupporting

confidence: 87%

“…The calculated reduction potential ( E calcd ) with respect to a reference electrode (ref) can be obtained with the following equation: where n is the number of electrons transferred during redox reactions, F is the Faraday constant of 23.06 kcal mol –1 V –1 , E calcd abs is the absolute reduction potential calculated by the quantum chemical simulation, E exptl,ref abs is the experimentally determined absolute reduction potential of a reference electrode, and Δ G soln,calcd is the calculated Gibbs free energy change in solution. The experimental reduction potential was reported against the standard calomel electrode (SCE); therefore, E exptl,ref abs was set to 4.521 V (standard hydrogen electrodeSHE: 4.281 V, and SCE vs SHE: 0.241 V). , …”

Section: Introductionmentioning

confidence: 99%

“…Quantum Chemical Simulation Details. The principal focus of this study are two types of reduction potentials (E): the potential associated with the direction in which an oxidized PC 48,49 The calculated reduction potential, E calcd 0 (E calcd * ), could be determined from the Gibbs free energy difference between PC + and PC 0 (PC*). The experimentally determined reduction potential in excited states, E exptl * , is the difference between E exptl 0 and the zero−zero transition energy (E zero−zero ), but the value of E zero−zero is not always available.…”

Section: ■ Introductionmentioning

confidence: 99%

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Spin-Flip Density Functional Theory for the Redox Properties of Organic Photoredox Catalysts in Excited States

Choi

2021

J. Chem. Theory Comput.

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Photoredox catalysts (PCs) have contributed to the advancement of organic chemistry by accelerating conventional reactions and enabling new pathways through the use of reactive electrons in excited states. With a number of successful applications, chemists continue to seek new promising organic PCs to achieve their objectives. Instead of labor-intensive manual experimentation, quantum chemical simulations could explore the enormous chemical space more efficiently. The reliability and accuracy of quantum chemical simulations have become important factors for material screening. We designed a theoretical protocol capable of predicting redox properties in excited states with high accuracy for a selected model system of dihydroquinoxalino[2,3-b]quinoxaline derivatives. Herein, three factors were considered as critical to achieving reliable predictions with accurate physics: the solvent medium effect on excited-state geometries, an adequate amount of Hartree–Fock exchange (HFX), and the consideration of double-excitation character in excited states. We determined that it is necessary to incorporate solvent medium during geometry optimizations to obtain planar excited-state structures that are consistent with the experimentally observed modest Stokes shift. While density functionals belonging to the generalized gradient approximation family perform well for the prediction of photoelectrochemical properties, an incorrect description of exciton boundedness (spontaneous dissociation of excitons or extremely weak boundedness) on small organic molecules was predicted. The inclusion of an adequate amount of Hartree–Fock exchange was suggested as one approach to obtain bound excitons, which is physically reasonable. The last consideration is the double-excitation character in S1 states. As revealed by the second-order algebraic diagrammatic construction theory, non-negligible double excitations exist in S1 states in our model systems. Time-dependent density functional theory (TDDFT) is blind to doubly excited states, and this motivated us to use spin-flip DFT (SF-DFT). We established a theoretical protocol that could provide highly accurate estimations of photophysical properties and ground-/excited-state redox properties, focusing on the three factors mentioned above. Geometry optimization with DFT and TDDFT employing the B3LYP functional (20% HFX) in solution and energy refinement by SF-DFT reproduced the experimental redox properties in the excited and ground states remarkably well with mean signed deviations (MSDs) of 0.01 and −0.15 V, respectively. This theoretical protocol is expected to contribute to the understanding of exciton behavior in organic PCs and to the efficient design of new promising PC candidates.

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Section: Resultssupporting

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

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Spin-Flip Density Functional Theory for the Redox Properties of Organic Photoredox Catalysts in Excited States

Choi

2021

J. Chem. Theory Comput.

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“…Although pure functionals are expected to provide similar accuracy as hybrid ones for predicting equilibrium geometries of DNA segments, , we have limited the present analysis to hybrid functionals because we are interested in the hole transfer in oxidized DNA, a phenomenon occurring through excited states with partial charge transfer character, for which pure functionals are not well suited. − …”

Section: Computational Detailsmentioning

confidence: 99%

Single-Stranded DNA Oligonucleotides Retain Rise Coordinates Characteristic of Double Helices

2018

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The structures of single-stranded DNA oligonucleotides from dimeric to hexameric sequences have been thoroughly investigated. Computations performed at the density functional level of theory including dispersion forces and solvation show that single-stranded helices adopt conformations very close to crystallographic B-DNA, with rise coordinates amounting up to 3.3 Å. Previous results, suggesting that single strands should be shorter than double helices, largely originated from the incompleteness of the adopted basis set. Although sensible deviations with respect to standard B-DNA are predicted, computations indicate that sequences rich in stacked adenines are the most ordered ones, favoring the B-DNA pattern and inducing regular arrangements also on flanking nucleobases. Several structural properties of double helices rich in adenine are indeed already reflected by the corresponding single strands.

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“…Computed BLA are reported in Table 5. For all the environments, ground state BLA's increases upon increasing the fraction of exact exchange in the functional, 66,67 as seen, e.g., by B3LYP and CAM* estimates in dioxane, amounting to 0.02 and 0.05 Å, respectively. Noteworthy, only functionals giving BLA ≥ 5 × 10 −2 Å at the ground state are capable of reproducing both the observed Δμ and the absorption band shape in low-polarity environments.…”

Section: ■ Resultsmentioning

confidence: 76%

Absorption Band Shapes of a Push–Pull Dye Approaching the Cyanine Limit: A Challenging Case for First Principle Calculations

et al. 2016

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The absorption band shapes of a solvent tunable donor-acceptor dye have been theoretically investigated by using Kubo's generating function approach, with minimum energy geometries and normal coordinates computed at the DFT level of theory. The adopted computational procedure allows us to include in the computation of Franck-Condon factors the whole set of normal modes, without any limitation on excitation quanta, allowing for an almost quantitative reproduction of the absorption band shape when the equilibrium geometries of the ground and the excited states are well predicted by electronic computations. Noteworthy, the functionals that yield more accurate band shapes also provide good prediction of the moment variations upon excitation; because the latter quantities are rarely available, theoretical simulation of band shapes could be a powerful tool for choosing the most appropriate computational method for predictive purposes.

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DFT predictions of the oxidation potential of organic dyes for opto-electronic devices

Cited by 12 publications

References 76 publications

Spin-Flip Density Functional Theory for the Redox Properties of Organic Photoredox Catalysts in Excited States

Spin-Flip Density Functional Theory for the Redox Properties of Organic Photoredox Catalysts in Excited States

Single-Stranded DNA Oligonucleotides Retain Rise Coordinates Characteristic of Double Helices

Absorption Band Shapes of a Push–Pull Dye Approaching the Cyanine Limit: A Challenging Case for First Principle Calculations

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