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Abstract The excited-state properties of molecular crystals are important for applications in organic electronic devices. TheGWapproximation and Bethe-Salpeter equation (GW+BSE) is the state-of-the-art method for calculating the excited-state properties of crystalline solids with periodic boundary conditions. We present the PAH101 dataset ofGW+BSE calculations for 101 molecular crystals of polycyclic aromatic hydrocarbons (PAHs) with up to ~500 atoms in the unit cell. To the best of our knowledge, this is the firstGW+BSE dataset for molecular crystals. The data records include theGWquasiparticle band structure, the fundamental band gap, the static dielectric constant, the first singlet exciton energy (optical gap), the first triplet exciton energy, the dielectric function, and optical absorption spectra for light polarized along the three lattice vectors. The dataset can be used to (i) discover materials with desired electronic/optical properties, (ii) identify correlations between DFT andGW+BSE quantities, and (iii) train machine learned models to help in materials discovery efforts.
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The role of crystal packing on the optical response of trialkyltetrelethynyl acenes
The electronic and optical responses of an organic semiconductor (OSC) are dictated by the chemistries of the molecular or polymer building blocks and how these chromophores pack in the solid state. Understanding the physicochemical nature of these responses is not only critical for determining the OSC performance for a particular application, but the UV/visible optical response may also be of potential use to determine aspects of the molecular-scale solid-state packing for crystal polymorphs or thin-film morphologies that are difficult to determine otherwise. To probe these relationships, we report the quantum-chemical investigation of a series of trialkyltetrelethynyl acenes (tetrel = silicon or germanium) that adopt the brickwork, slip-stack, or herringbone (HB) packing configurations; the π-conjugated backbones considered here are pentacene and anthradithiophene. For comparison, HB-packed (unsubstituted) pentacene is also included. Density functional theory and G 0 W 0 (single-shot Green’s function G and/or screened Coulomb function W) electronic band structures, G 0 W 0 -Bethe–Salpeter equation-derived optical spectra, polarized ϵ 2 spectra, and distributions of both singlet and triplet exciton wave functions are reported. Configurational disorder is also considered. Furthermore, we evaluate the probability of singlet fission in these materials through energy conservation relationships.
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- Award ID(s):
- 1849213
- PAR ID:
- 10410823
- Date Published:
- Journal Name:
- The Journal of Chemical Physics
- Volume:
- 157
- Issue:
- 8
- ISSN:
- 0021-9606
- Page Range / eLocation ID:
- 084703
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Crystalline pentacene is a model solid-state light-harvesting material because its quantum efficiencies exceed 100% via ultrafast singlet fission. The singlet fission mechanism in pentacene crystals is disputed due to insufficient electronic information in time-resolved experiments and intractable quantum mechanical calculations for simulating realistic crystal dynamics. Here we combine a multiscale multiconfigurational approach and machine learning photodynamics to understand competing singlet fission mechanisms in crystalline pentacene. Our simulations reveal coexisting charge-transfer-mediated and coherent mechanisms via the competing channels in the herringbone and parallel dimers. The predicted singlet fission time constants (61 and 33 fs) are in excellent agreement with experiments (78 and 35 fs). The trajectories highlight the essential role of intermolecular stretching between monomers in generating the multi-exciton state and explain the anisotropic phenomenon. The machine-learning-photodynamics resolved the elusive interplay between electronic structure and vibrational relations, enabling fully atomistic excited-state dynamics with multiconfigurational quantum mechanical quality for crystalline pentacene.more » « less
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Hydrogen bonding (HB) interactions are well known to impact the properties of water in the bulk and within hydrated materials. A series of Ni( ii ) complexes based on chelates containing N -(2-aminoethyl)-1-methylimidazole-2-carboxamide have been synthesized and fully characterized by single crystal X-ray diffraction, spectroscopic methods, and thermal analysis. The complexes reveal a variety of water cluster motifs dependent on the packing arrangement in the solid state. A key feature is the orientation of the carboxamide moiety, which leads to the formation of void spaces that accommodate water through HB interactions. The water motifs contain 1D water chains (streams), 2D tapes of infused rings (cascades), and isolated water dimers (pools). The HB motifs in the hydrated structures vary as a function of the crystal packing of the host molecules. Thermal analyses show a correlation between the HB motif in the hydrated crystals and the temperature range of the dehydration process. The conductivity of the hydrated crystals varies as a function of the crystal packing interactions between metal complexes.more » « less
- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1063/5.0097421
