Structural Differences between ππ* and nπ* Acetophenone Triplet Excited States as Revealed by Time-Resolved IR Spectroscopy

1998 ◽  
Vol 120 (24) ◽  
pp. 6173-6174 ◽  
Author(s):  
Sanjay Srivastava ◽  
Emily Yourd ◽  
John P. Toscano
Keyword(s):  
Ir Spectroscopy ◽  
Excited States ◽  
Time Resolved ◽  
Structural Differences ◽  
Triplet Excited States

Bond Shortening (1.4 Å) in the Singlet and Triplet Excited States of [Ir2(dimen)4]2+in Solution Determined by Time-Resolved X-ray Scattering

2011 ◽  
Vol 50 (19) ◽  
pp. 9329-9336 ◽  
Author(s):  
Kristoffer Haldrup ◽  
Tobias Harlang ◽  
Morten Christensen ◽  
Asmus Dohn ◽  
Tim Brandt van Driel ◽  
...  
Keyword(s):  
Excited States ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
Triplet Excited States ◽  
Ray Scattering

Combined theoretical and time-resolved photoluminescence investigations of [Mo6Bri8Bra6]2− metal cluster units: evidence of dual emission

2015 ◽  
Vol 17 (43) ◽  
pp. 28574-28585 ◽  
Author(s):  
K. Costuas ◽  
A. Garreau ◽  
A. Bulou ◽  
B. Fontaine ◽  
J. Cuny ◽  
...  
Keyword(s):  
Excited States ◽  
Metal Cluster ◽  
Energy Shift ◽  
Dual Emission ◽  
Time Resolved ◽  
Nir Emission ◽  
Triplet Excited States ◽  
Time Resolved Photoluminescence

Distinct emissive species have been identified in [Mo6Bri8Bra6]2− containing systems. Strong geometrical relaxations of the triplet excited states are responsible for the huge energy shift leading to intense red-NIR emission.

scholarly journals Manipulating spatial alignment of donor and acceptor in host-guest MOF for TADF

2021 ◽  
Author(s):  
Xiao-Ting Liu ◽  
Weijie Hua ◽  
Hong-Xiang Nie ◽  
Mingxing Chen ◽  
Ze Chang ◽  
...  
Keyword(s):  
Excited States ◽  
Delayed Fluorescence ◽  
Energy Splitting ◽  
Time Resolved ◽  
Face To Face ◽  
Spatial Alignment ◽  
Stacking Pattern ◽  
Donor And Acceptor ◽  
Loading Ratio ◽  
Triplet Excited States

Abstract Thermally activated delayed fluorescence (TADF) was achieved when electron-rich triphenylene (Tpl) donors (D) were confined to a cage-based porous MOF host (NKU-111) composed of electron-deficient 2,4,6-tri(pyridin-4-yl)-1,3,5-triazine (Tpt) acceptor (A) as the ligand. The spatially-separated D and A molecules in a face-to-face stacking pattern generated strong through-space charge transfer (CT) interactions with a small singlet-triplet excited states energy splitting (∼0.1 eV), which enabled TADF. The resulting Tpl@NKU-111 exhibited an uncommon enhanced emission intensity as the temperature increased. Extensive steady-state and time-resolved spectroscopic measurements and first-principles simulations revealed the chemical and electronic structure of this compound in both the ground and low-lying excited states. A double-channel (T1, T2) intersystem crossing mechanism with S1 was found and explained as single-directional CT from the degenerate HOMO-1/HOMO of the guest donor to the LUMO + 1 of one of the nearest acceptors. The rigid skeleton of the compound and effective through-space CT enhanced the photoluminescence quantum yield (PLQY). A maximum PLQY of 57.36% was achieved by optimizing the Tpl loading ratio in the host framework. These results indicate the potential of the MOFs for the targeted construction and optimization of TADF materials.

Direct Observation of 1,2-Hydrogen Migration in the Excited States of Alkyl Diazo Esters by Ultrafast Time Resolved IR Spectroscopy

2010 ◽  
Vol 132 (7) ◽  
pp. 2126-2127 ◽  
Author(s):  
Gotard Burdzinski ◽  
Yunlong Zhang ◽  
Peter Selvaraj ◽  
Michel Sliwa ◽  
Matthew S. Platz
Keyword(s):  
Ir Spectroscopy ◽  
Excited States ◽  
Direct Observation ◽  
Time Resolved ◽  
Hydrogen Migration ◽  
Diazo Esters

Optimization of a Safranine O three-component photoinitiating system for use in holographic recording

2015 ◽  
Vol 93 (12) ◽  
pp. 1345-1353 ◽  
Author(s):  
Ahmad Ibrahim ◽  
Bandar El Fouhaili ◽  
Aurélie Chan Yong ◽  
Christian Ley ◽  
Xavier Allonas ◽  
...  
Keyword(s):  
Excited States ◽  
Irradiation Time ◽  
Holographic Recording ◽  
Time Resolved ◽  
The Matrix ◽  
Resin Formulation ◽  
High Diffraction Efficiency ◽  
Triplet Excited States ◽  
Safranine O ◽  
High Diffraction

The coupling between a holographic resin, combining multiple monomers and additives, with photoinitiating systems (PIS) is not straightforward. In this paper, a classic PIS based on Safranine O (SFH+) as dye, an amine (ethyl-4-(dimethylamino)benzoate) as electron donor, and a triazine derivative (2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-1,3,5-triazine) as electron acceptor for holographic recording was studied using time-resolved spectroscopic experiments. By taking into account the viscosity of the matrix, a method to evaluate the overall quantum yield of radicals released is proposed and the contribution of singlet and triplet excited states of SFH+ in the formation of radicals is evaluated. Then the corresponding photopolymerization efficiencies of the PIS, studied by real-time FTIR, are compared with holographic recording experiments: this system allows the formation of a hologram with high diffraction efficiency (0.9) in 3 s of irradiation time. It is shown that besides holographic resin formulation, the photochemistry of PIS also impacts the hologram formation.

Electronic Structure and Excited States of Rhenium(I) Amido and Phosphido Carbonyl−Bipyridine Complexes Studied by Picosecond Time-Resolved IR Spectroscopy and DFT Calculations

2006 ◽  
Vol 45 (24) ◽  
pp. 9789-9797 ◽  
Author(s):  
Anders Gabrielsson ◽  
Michael Busby ◽  
Pavel Matousek ◽  
Michael Towrie ◽  
Eva Hevia ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Ir Spectroscopy ◽  
Dft Calculations ◽  
Excited States ◽  
Time Resolved

scholarly journals Structure-Reactivity Correlations of Excited States of Perfluorinated Compounds: A Time Resolved Raman Study

1999 ◽  
Vol 19 (1-4) ◽  
pp. 343-348 ◽  
Author(s):  
R. Anandhi ◽  
G. Balakrishnan ◽  
P. Mohandas ◽  
S. Umapathy
Keyword(s):  
Excited States ◽  
Ground State ◽  
Perfluorinated Compounds ◽  
Spectral Studies ◽  
Triplet Excited State ◽  
Time Resolved ◽  
Organic Systems ◽  
Structural Distortions ◽  
Raman Study ◽  
Triplet Excited States

This paper reports the TR3 spectral studies on perfluorinated organic systems with the objective to understand the influence of perfluorination on the excited states. We have recorded the TR3 spectra and Raman excitation profiles of the triplet excited states of decafluorobenzophenone and fluoranil. It is found that the influence of perfluorination is more pronounced in the triplet excited state than the ground state and thus leads to enhanced reactivity for perfluorinated compounds through larger structural distortions.

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