Abstract
Discussion Forum (0)
Nanoscale devices using transition metals have shown promise in the renewable energy context for their robustness and scalability. In artificial photosynthetic devices, light harvesting molecules drive reactions which create fuel (e.g by splitting water). For optimal fuel generation efficiency a long charge transfer excited state lifetime is necessary. In this study, we considered the experimentally synthesized vanadium(V) oxo compound VOLF (where LF is N(CH2Ar2)((CH2)2OH) with Ar= (2-hydroxy-5-fluoro-3- methyl)phenyl) which has been observed to remain in the optically excited state for 438 ps. We used linear response time dependent density functional theory (TD-DFT) to compute and interpret static UV-Vis spectra and ultrafast transient absorption. To assess effects due to finite temperature, we used first principles molecular dynamics to generate multiple starting configurations in different solvent environments. Additionally, we modelled the time dependence of the transient absorption spectra. Comparing with experiment, we find good agreement with the observed spectra. Furthermore, we find that the bright state is associated with charge transfer to the vanadium from surrounding ligands. Our results suggest transitions between low lying d- states cause relaxation to the ground state to be both dipole and vibronically forbidden. This phenomenon gives rise to extended excited state lifetimes.
Nanoscale devices using transition metals have shown promise in the renewable energy context for their robustness and scalability. In artificial photosynthetic devices, light harvesting molecules drive reactions which create fuel (e.g by splitting water). For optimal fuel generation efficiency a long charge transfer excited state lifetime is necessary. In this study, we considered the experimentally synthesized vanadium(V) oxo compound VOLF (where LF is N(CH2Ar2)((CH2)2OH) with Ar= (2-hydroxy-5-fluoro-3- methyl)phenyl) which has been observed to remain in the optically excited state for 438 ps. We used linear response time dependent density functional theory (TD-DFT) to compute and interpret static UV-Vis spectra and ultrafast transient absorption. To assess effects due to finite temperature, we used first principles molecular dynamics to generate multiple starting configurations in different solvent environments. Additionally, we modelled the time dependence of the transient absorption spectra. Comparing with experiment, we find good agreement with the observed spectra. Furthermore, we find that the bright state is associated with charge transfer to the vanadium from surrounding ligands. Our results suggest transitions between low lying d- states cause relaxation to the ground state to be both dipole and vibronically forbidden. This phenomenon gives rise to extended excited state lifetimes.
Computational Materials Science Part II
Disclosure(s): Paper No: 8766Presenter: Graham Clendenning, University of Ontario, Institute of TechnologyAuthor(s): Mr. Graham Clendenning, University of Ontario Institute of Technology; Ms. Stephanie Choing, University of California, Berkeley; Mr. Aaron Francis, North Carolina State University; Michael S. Shuurman, National Research Council; Roger D. Sommer, North Carolina State University; Mr. Walter Weare, North Carolina State University; Ms. Tanja Cuk, University of California, Berkeley; Mr. Isaac Tamblyn, University of Ontario Institute of TechnologyA special thank you to the author(s) and affiliates.Copyright of Congress Digital Content is held by the author and not the Organizing Society/Body and was released with the consent of the author(s)/company permission.
Graham Clendenning
Abstract
Discussion Forum (0)
Nanoscale devices using transition metals have shown promise in the renewable energy context for their robustness and scalability. In artificial photosynthetic devices, light harvesting molecules drive reactions which create fuel (e.g by splitting water). For optimal fuel generation efficiency a long charge transfer excited state lifetime is necessary. In this study, we considered the experimentally synthesized vanadium(V) oxo compound VOLF (where LF is N(CH2Ar2)((CH2)2OH) with Ar= (2-hydroxy-5-fluoro-3- methyl)phenyl) which has been observed to remain in the optically excited state for 438 ps. We used linear response time dependent density functional theory (TD-DFT) to compute and interpret static UV-Vis spectra and ultrafast transient absorption. To assess effects due to finite temperature, we used first principles molecular dynamics to generate multiple starting configurations in different solvent environments. Additionally, we modelled the time dependence of the transient absorption spectra. Comparing with experiment, we find good agreement with the observed spectra. Furthermore, we find that the bright state is associated with charge transfer to the vanadium from surrounding ligands. Our results suggest transitions between low lying d- states cause relaxation to the ground state to be both dipole and vibronically forbidden. This phenomenon gives rise to extended excited state lifetimes.
Nanoscale devices using transition metals have shown promise in the renewable energy context for their robustness and scalability. In artificial photosynthetic devices, light harvesting molecules drive reactions which create fuel (e.g by splitting water). For optimal fuel generation efficiency a long charge transfer excited state lifetime is necessary. In this study, we considered the experimentally synthesized vanadium(V) oxo compound VOLF (where LF is N(CH2Ar2)((CH2)2OH) with Ar= (2-hydroxy-5-fluoro-3- methyl)phenyl) which has been observed to remain in the optically excited state for 438 ps. We used linear response time dependent density functional theory (TD-DFT) to compute and interpret static UV-Vis spectra and ultrafast transient absorption. To assess effects due to finite temperature, we used first principles molecular dynamics to generate multiple starting configurations in different solvent environments. Additionally, we modelled the time dependence of the transient absorption spectra. Comparing with experiment, we find good agreement with the observed spectra. Furthermore, we find that the bright state is associated with charge transfer to the vanadium from surrounding ligands. Our results suggest transitions between low lying d- states cause relaxation to the ground state to be both dipole and vibronically forbidden. This phenomenon gives rise to extended excited state lifetimes.
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