Organic light emitting diodes (OLEDs) based on thermally activated delayed fluorescence (TADF) emitters are an attractive category of materials that have witnessed a booming development in recent years. In the present contribution, we scrutinize the accountability of parameterized and parameter-free single-hybrid (SH) and double-hybrid (DH) functionals through the two formalisms, full time-dependent density functional theory (TD-DFT) and Tamm-Dancoff approximation (TDA), for the estimation of photophysical properties like absorption energy, emission energy, zero-zero transition energy, and singlet-triplet energy splitting of TADF molecules. According to our detailed analyses on the performance of SHs based on TD-DFT and TDA, the TDA-based parameter-free SH functionals, PBE0 and TPSS0, with one-third of exact-like exchange turned out to be the best performers in comparison to other functionals from various rungs to reproduce the experimental data of the benchmarked set. Such affordable SH approximations can thus be employed to predict and design the TADF molecules with low singlet-triplet energy gaps for OLED applications. From another perspective, considering this point that both the nonlocal exchange and correlation are essential for a more reliable description of large charge-transfer excited states, applicability of the functionals incorporating these terms, namely, parameterized and parameter-free DHs, has also been evaluated. Perusing the role of exact-like exchange, perturbative-like correlation, solvent effects, and other related factors, we find that the parameterized functionals B2π-PLYP and B2GP-PLYP and the parameter-free models PBE-CIDH and PBE-QIDH have respectable performance with respect to others. Lastly, besides the recommendation of reliable computational protocols for the purpose, hopefully this study can pave the way toward further developments of other SHs and DHs for theoretical explorations in the field of OLEDs technology.
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http://dx.doi.org/10.1063/1.4986777 | DOI Listing |
J Phys Chem A
September 2023
Department of Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61820, United States.
It is widely accepted that energetics of chemical bond breaking and formation can be described with simple mathematical forms only at the expense of extensive parameterization. In this work, the discovery of a simple tight-binding-type mathematical framework that can accurately predict the relative energetics of regular H polygons (2 ≤ ≤ 15) in the ground states with their respective spin multiplicities using no parameters has been reported. The framework recasts Hückel theory in a density functional theory form by making use of Anderson and Adams-Gilbert theories of localized orbitals.
View Article and Find Full Text PDFJ Comput Chem
April 2023
Algorithms-Biology-Structure, Centre Inria at Université Côte d'Azur, Sophia Antipolis, France.
Flexible loops are paramount to protein functions, with action modes ranging from localized dynamics contributing to the free energy of the system, to large amplitude conformational changes accounting for the repositioning whole secondary structure elements or protein domains. However, generating diverse and low energy loops remains a difficult problem. This work introduces a novel paradigm to sample loop conformations, in the spirit of the hit-and-run (HAR) Markov chain Monte Carlo technique.
View Article and Find Full Text PDFACS Omega
August 2022
Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9712 CP Groningen, The Netherlands.
Single-molecule nanopore electrophysiology is an emerging technique for the detection of analytes in aqueous solutions with high sensitivity. These detectors have proven applicable for the enzyme-assisted sequencing of oligonucleotides. There has recently been an increased interest in the use of nanopores for the fingerprinting of peptides and proteins, referred to as single-molecule nanopore spectrometry.
View Article and Find Full Text PDFPhys Chem Chem Phys
March 2022
Dipartimento di Scienze Chimiche, Università degli Studi di Padova, Via Marzolo 1, Padova, Italy.
We estimate the kinetic constants of a series of archetypal S2 reactions, , the nucleophilic substitutions of halides in halomethane. A parameter free, multiscale approach recently developed [Campeggio , , 2020, , 3455] is employed. The protocol relies on quantum mechanical calculations for the description of the energy profile along the intrinsic reaction coordinate, which is then mapped onto a reaction coordinate conveniently built for the reactive process.
View Article and Find Full Text PDFJ Chem Phys
February 2022
Department of Chemistry, School of Science, Shiraz University, Shiraz 71946-84795, Iran.
Organic emissive materials with the inverted singlet-triplet energy gaps, where in violation of Hund's multiplicity rule the lowest triplet excited-state is higher in energy than the lowest singlet excited-state, have recently come into the limelight. This unique feature is of important relevance, where the emitters meeting the singlet-triplet inversion have potential to usher in the next generation of organic light emitting diodes (OLEDs). Since experimental data in this context are currently sparse, necessity of the cost-effective theoretical tools able to provide reliable results seems to be evident.
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