scholarly journals Emission Quenching in Tetraphenylfuran Crystal: Why This Propeller-Shaped Molecule Does Not Emit in the Condensed Phase?

Molecules ◽  
2022 ◽  
Vol 27 (2) ◽  
pp. 522
Author(s):  
Ljiljana Stojanović ◽  
Rachel Crespo-Otero
Keyword(s):  
Solid State ◽  
Ground State ◽  
Light Emission ◽  
Quantum Yields ◽  
Triplet States ◽  
Fluorescence Quantum Yields ◽  
The Family ◽  
Emission Quenching ◽  
Significant Attention

Due to their substantial fluorescence quantum yields in the crystalline phase, propeller-shaped molecules have recently gained significant attention as potential emissive materials for optoelectronic applications. For the family of cyclopentadiene derivatives, light-emission is highly dependent on the nature of heteroatomic substitutions. In this paper, we investigate excited state relaxation pathways in the tetraphenyl-furan molecule (TPF), which in contrast with other molecules in the family, shows emission quenching in the solid-state. For the singlet manifold, our calculations show nonradiative pathways associated with C-O elongation are blocked in both vacuum and the solid state. A fraction of the population can be transferred to the triplet manifold and, subsequently, to the ground state in both phases. This process is expected to be relatively slow due to the small spin-orbit couplings between the relevant singlet-triplet states. Emission quenching in crystalline TPF seems to be in line with more efficient exciton hopping rates. Our simulations help clarify the role of conical intersections, population of the triplet states and crystalline structure in the emissive response of propeller-shaped molecules.

scholarly journals Aggregation Induced Emission in the Tetraphenylthiophene Crystal: The Role of Triplet States

2020 ◽  
Author(s):  
Ljiljana Stojanovic ◽  
Rachel Crespo Otero
Keyword(s):  
Solid State ◽  
Potential Energy Surfaces ◽  
Special Focus ◽  
Intersystem Crossing ◽  
Triplet States ◽  
Aggregation Induced Emission ◽  
The Family ◽  
Energy Surfaces ◽  
Potential Use

<p>Propeller-shaped molecules have received much attention due to their enhanced emission in the condensed phase (Aggregation Induced Emission, AIE) and their potential use in optoelectronic devices. In this contribution, we examine the excited state mechanisms of tetraphenyl-thiophene (TPT), one member of the family which features weaker AIE. We perform a detailed analysis of the potential energy surfaces with special focus on the role of triplet states considering the crystal structure, intermolecular interactions, exciton couplings and reorganisation energies in the vacuum and solid state. In contrast with other members of the propeller-shaped family, nonradiative decay in TPT is driven by bond breaking. Because of the significant spin-orbit couplings along the reaction coordinate, intersystem crossing plays an important role in the mechanism. Our calculations show that aggregation in the solid state hampers the access to internal conversion pathways, however, intersystem crossing is active in the crystal phase, which explains the weak AIE of this molecule. This new understanding of the role of triplet states on the relaxation mechanisms of AIEgens has implications for the design of solid state highly-emissive materials based on TPT.<br></p>

scholarly journals Aggregation Induced Emission in the Tetraphenylthiophene Crystal: The Role of Triplet States

2020 ◽  
Author(s):  
Ljiljana Stojanovic ◽  
Rachel Crespo Otero
Keyword(s):  
Solid State ◽  
Potential Energy Surfaces ◽  
Special Focus ◽  
Intersystem Crossing ◽  
Triplet States ◽  
Aggregation Induced Emission ◽  
The Family ◽  
Energy Surfaces ◽  
Potential Use

<p>Propeller-shaped molecules have received much attention due to their enhanced emission in the condensed phase (Aggregation Induced Emission, AIE) and their potential use in optoelectronic devices. In this contribution, we examine the excited state mechanisms of tetraphenyl-thiophene (TPT), one member of the family which features weaker AIE. We perform a detailed analysis of the potential energy surfaces with special focus on the role of triplet states considering the crystal structure, intermolecular interactions, exciton couplings and reorganisation energies in the vacuum and solid state. In contrast with other members of the propeller-shaped family, nonradiative decay in TPT is driven by bond breaking. Because of the significant spin-orbit couplings along the reaction coordinate, intersystem crossing plays an important role in the mechanism. Our calculations show that aggregation in the solid state hampers the access to internal conversion pathways, however, intersystem crossing is active in the crystal phase, which explains the weak AIE of this molecule. This new understanding of the role of triplet states on the relaxation mechanisms of AIEgens has implications for the design of solid state highly-emissive materials based on TPT.<br></p>

scholarly journals Indenopyrans – synthesis and photoluminescence properties

2016 ◽  
Vol 12 ◽  
pp. 825-834 ◽  
Author(s):  
Andreea Petronela Diac ◽  
Ana-Maria Ţepeş ◽  
Albert Soran ◽  
Ion Grosu ◽  
Anamaria Terec ◽  
...  
Keyword(s):  
Solid State ◽  
Emission Band ◽  
Fluorescence Spectra ◽  
Photophysical Properties ◽  
Quantum Yields ◽  
Band Broadening ◽  
Photoluminescence Properties ◽  
Fluorescence Quantum Yields ◽  
Blue Emitters ◽  
Solid State Fluorescence

New indeno[1,2-c]pyran-3-ones bearing different substituents at the pyran moiety were synthesized and their photophysical properties were investigated. In solution all compounds were found to be blue emitters and the trans isomers exhibited significantly higher fluorescence quantum yields (relative to 9,10-diphenylanthracene) as compared to the corresponding cis isomers. The solid-state fluorescence spectra revealed an important red shift of λmax due to intermolecular interactions in the lattice, along with an emission-band broadening, as compared to the solution fluorescence spectra.

Steric Effects in the Electronic Spectra of the 3,5-Diarylaminobenzene Derivatives

1986 ◽  
Vol 41 (11) ◽  
pp. 1311-1314 ◽  
Author(s):  
A. Balter ◽  
W. Nowak ◽  
P. Milart ◽  
J. Sepioł
Keyword(s):  
Excited State ◽  
Electronic Spectra ◽  
Fluorescence Properties ◽  
Steric Effects ◽  
Quantum Yields ◽  
Spectroscopic Behaviour ◽  
Fluorescence Quantum Yields ◽  
Excited State Lifetimes ◽  
Methyl Phenyl

Absorption and fluorescence properties, excited state lifetimes and fluorescence quantum yields were determined for a series of 3,5-diarylaminobenzene derivatives in solvents of different polarities. The role of the nitrile, methyl, phenyl and naphthyl substituents is discussed. Especially the steric effects on the spectroscopic behaviour of the investigated molecules are studied.

scholarly journals Towards Blue AIE/AIEE: Synthesis and Applications in OLEDs of Tetra-/Triphenylethenyl Substituted 9,9-Dimethylacridine Derivatives

Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 445 ◽  
Author(s):  
Monika Cekaviciute ◽  
Aina Petrauskaite ◽  
Sohrab Nasiri ◽  
Jurate Simokaitiene ◽  
Dmytro Volyniuk ◽  
...  
Keyword(s):  
Solid State ◽  
Quantum Yields ◽  
Yellow Emission ◽  
Blue Color ◽  
Television System ◽  
Fluorescence Quantum Yields ◽  
Deep Blue ◽  
Wide Range ◽  
Cyano Groups ◽  
High Yields

Aiming to design blue fluorescent emitters with high photoluminescence quantum yields in solid-state, nitrogen-containing heteroaromatic 9,9-dimethylacridine was refined by tetraphenylethene and triphenylethene. Six tetra-/triphenylethene-substituted 9,9-dimethylacridines were synthesized by the Buchwald-Hartwig method with relatively high yields. Showing effects of substitution patterns, all emitters demonstrated high fluorescence quantum yields of 26–53% in non-doped films and 52–88% in doped films due to the aggregation induced/enhanced emission (AIE/AIEE) phenomena. In solid-state, the emitters emitted blue (451–481 nm) without doping and deep-blue (438–445 nm) with doping while greenish-yellow emission was detected for two compounds with additionally attached cyano-groups. The ionization potentials of the derivatives were found to be in the relatively wide range of 5.43–5.81 eV since cyano-groups were used in their design. Possible applications of the emitters were demonstrated in non-doped and doped organic light-emitting diodes with up to 2.3 % external quantum efficiencies for simple fluorescent devices. In the best case, deep-blue electroluminescence with chromaticity coordinates of (0.16, 0.10) was close to blue color standard (0.14, 0.08) of the National Television System Committee.

scholarly journals The Role of Percent Volume Buried in the Characterization of Copper(I) Complexes for Lighting Purposes

Molecules ◽  
2020 ◽  
Vol 25 (11) ◽  
pp. 2647 ◽  
Author(s):  
Murat Alkan-Zambada ◽  
Edwin C. Constable ◽  
Catherine E. Housecroft
Keyword(s):  
Solid State ◽  
Single Crystal ◽  
Quantum Yields ◽  
X Ray ◽  
Photophysical Behavior

The usefulness of percent volume buried (%Vbur) as a readily quantifiable property is investigated with regard to [Cu(NN)(PP)]+ complexes of interest for lighting purposes. Photoluminescence quantum yields (PLQYs) and single crystal X-ray structures of 100 reported compounds were assembled, %Vbur of the ligand systems were calculated and analyzed for correlations. We found that increased shielding of the central Cu(I) cation relying on shared contributions of both (NN) and (PP) ligand systems led to increased PLQYs. These findings are of relevance for future characterizations of Cu(I)-based complexes and their photophysical behavior in the solid-state.

Properties of singlet- and triplet-excited states of hemicyanine dyes

2014 ◽  
Vol 68 (8) ◽  
Author(s):  
Daniel Mártire ◽  
Walter Massad ◽  
Hernán Montejano ◽  
Mónica Gonzalez ◽  
Paula Caregnato ◽  
...  
Keyword(s):  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Laser Flash ◽  
Quantum Yields ◽  
Triplet States ◽  
Fluorescence Emission Spectra ◽  
Fluorescence Quantum Yields ◽  
Hemicyanine Dyes

AbstractThe fluorescence emission spectra and fluorescence quantum yields of hemicyanine dyes LDS 698, LDS 722, and LDS 730 were measured in different media. No transient species was detected in the laser flash-photolysis experiments performed with Ar-saturated solutions of the dyes in methanol. However, in the presence of 0.08 M potassium iodide, the absorption of the triplet states was clearly observed. Oxygen consumption measurements in the absence and presence of a chemical trap (furfuryl alcohol) in MeOH: H2O (φ r = 1: 1) solutions of the dyes containing KI confirmed the generation of singlet molecular oxygen.

scholarly journals Excimeric Emission and Photochemical Behavior of p-Phenylenediacrylic Acid (p-PDA) and its Diethyl-Ester (p-PDAEt)

1985 ◽  
Vol 5 (5) ◽  
pp. 309-319 ◽  
Author(s):  
El-Zeiny M. Ebeid ◽  
Samy A. El-Daly ◽  
Masaki Hasegawa
Keyword(s):  
Diethyl Ester ◽  
Quantum Yields ◽  
Triplet States ◽  
Cetyltrimethylammonium Chloride ◽  
Concentrated Solutions ◽  
Molecular Emission ◽  
Fluorescence Quantum Yields ◽  
Emission Maximum ◽  
Cationic Micelles ◽  
Photoisomerization Process

p-Phenylenediacrylic acid (p-PDA) displays excimeric emission in concentrated solutions (concentration ca. 0.5 M) in dimethylsulphoxide (DMSO). The excimeric emission maximum is red shifted by ca. 5200 cm–1 compared with molecular emission maximum. The fluorescence quantum yields of p-PDA has been measured in DMSO (φf = 0.09, λex = 337 nm) and in cetyltrimethylammonium chloride (CTAC) cationic micelles that show remarkable solubilization of p-PDA.The solution photoreactivity of p-PDA is wavelength dependent. In dilute DMSO solutions, 365 nm and 310 nm light causes p-PDA consumption giving a photoproduct of maximum absorption at ca. 265 n,. A back photoreaction is induced by 254 nm light. The photochemical quantum yields (φc) of the forward photochemical reaction have been measured as a function of temperature and the activation energy was evaluated as Ea = 9 kJ mol–1 suggesting a unimolecular photoisomerization process.Emission from crystalline p-PDA has also been reported. The emission maximum is red shifted from molecular emission maximum by ca. 3250 cm–1.The energy transfer in the system diethyl-p-phenylenediacrylate (p-PDAEt)-1,4-bis(β-pyridyl-2-vinyl)benzene(P2VB) has been studied. Triplet states formation mechanism is proposed.

scholarly journals Mono-, Di-, Tri-Pyrene Substituted Cyclic Triimidazole: A Family of Highly Emissive and RTP Chromophores

Photochem ◽  
2021 ◽  
Vol 1 (3) ◽  
pp. 477-487
Author(s):  
Daniele Malpicci ◽  
Clelia Giannini ◽  
Elena Lucenti ◽  
Alessandra Forni ◽  
Daniele Marinotto ◽  
...  
Keyword(s):  
Steady State ◽  
Solid State ◽  
Intermolecular Interactions ◽  
Quantum Yields ◽  
Time Resolved ◽  
Tddft Calculations ◽  
Pyrene Molecule ◽  
The Family ◽  
Strong Motivation

The search of new organic emitters is receiving a strong motivation by the development of ORTP materials. In the present study we report on the preparation, optical and photophysical characterization, by both steady state and time resolved techniques, of two pyrene-functionalized cyclic triimidazole derivatives. Together with the already reported mono-substituted derivative, the di- and tri-substituted members of the family have revealed as intriguing emitters characterized by impressive quantum yields in solution and RTP properties in the solid state. In particular, phosphorescence lifetimes increase from 5.19 to 20.54 and 40.62 ms for mono-, di- and trisubstituted compounds, respectively. Based on spectroscopical results and theoretical DFT/TDDFT calculations on the di-pyrene molecule, differences in photophysical performances of the three compounds have been assigned to intermolecular interactions increasing with the number of pyrene moieties appended to the cyclic triimidazole scaffold.

Highly fluorescent triazolopyridine–thiophene D–A–D oligomers for efficient pH sensing both in solution and in the solid state

2019 ◽  
Vol 21 (13) ◽  
pp. 7174-7182 ◽  
Author(s):  
Nannan Jian ◽  
Kai Qu ◽  
Hua Gu ◽  
Lie Zou ◽  
Ximei Liu ◽  
...  
Keyword(s):  
Solid State ◽  
Fluorescence Quenching ◽  
Quantum Yields ◽  
Ph Sensing ◽  
Fluorescence Quantum Yields ◽  
High Fluorescence ◽  
Printed Patterns

Triazolopyridine–thiophene fluorophores exhibit high fluorescence quantum yields both in solution (80–89%) and in the solid state (13–26%). Because of an excellent and reversible pH induced fluorescence quenching/recovery, sensing devices such as fluorescent papers and complex inkjet-printed patterns are successfully fabricated for the detection of volatile acids both in solution and in a vapor atmosphere.

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