scholarly journals 1,4-Bis (β-Pyridyl-2-Vinyl) Benzene (P2VB) and 2,5-Distyryl-pyrazine (DSP) as Blue Laser Dyes

1985 ◽  
Vol 5 (4) ◽  
pp. 223-230 ◽  
Author(s):  
E. M. Ebeid ◽  
M. M. F. Sabry ◽  
S. A. El-Daly
Keyword(s):  
Energy Transfer ◽  
Laser Excitation ◽  
Blue Laser ◽  
Quantum Yields ◽  
Nitrogen Laser ◽  
Laser Dyes ◽  
Energy Transfer Mechanism ◽  
Fluorescence Quantum Yields ◽  
Critical Transfer Distance

Solutions of P2VB and DSP in dimethyl-sulphoxide (DMSO) of concentration ca. 10–3 M/l act as laser dyes on pumping with nitrogen laser. P2VB and DSP are lasing in the ranges 390–440 nm (λmax = 416 nm) and 435–465 nm (λmax = 447 nm) respectively. An equimolar mixture of P2VB and DSP behaves as an energy transfer dye laser (ETDL) and is lasing in the range 429–455 nm (λmax = 438 nm). Such ETDL system obeys a long range coulombic energy transfer mechanism with a critical transfer distance R0 = 7.5 nm.The fluorescence quantum yields of both dyes have been measured, and in DMSO φf = 0.46 and 0.35 for P2VB and DSP respectively.Both dyes show a remarkable photostability upon nitrogen laser excitation. This has been attributed to the role of the 337 nm light in inducing a back photo-chemical reaction of the initially formed photoproducts consisting mainly of photo-oligomers and cis-photoisomers.

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.

Fluorescence Quantum Yields of Laser Dyes Determined by On-Line Computer Evaluation

1982 ◽  
Vol 37 (3) ◽  
pp. 219-223 ◽  
Author(s):  
Günter Gauglitz ◽  
Alwin Lorch ◽  
Dieter Oelkrug
Keyword(s):  
Dark Current ◽  
Optimal Choice ◽  
Quantum Yields ◽  
Excitation Wavelength ◽  
Laser Dyes ◽  
Correction Procedure ◽  
Fluorescence Quantum Yields ◽  
On Line ◽  
Better Than

Abstract The determination of relative fluorescence quantum yields has been improved to better than 3% precision by use of a multichannel analyzer and an on-line desk-top computer. The new combined device for data acquisition and handling as well as a new correction procedure are described. Drifts of excitation source and dark current can be omitted. The yields for laser dyes, emitting at short wavelengths, are presented in dependence on excitation wavelength. These results simplify the optimal choice of the pump conditions of laser dyes, which usually are not photostable.

H2O2-activated triplet–triplet annihilation upconversion via modulation of the fluorescence quantum yields of the triplet acceptor and the triplet–triplet-energy-transfer efficiency

2015 ◽  
Vol 51 (62) ◽  
pp. 12403-12406 ◽  
Author(s):  
Renjie Tao ◽  
Jianzhang Zhao ◽  
Fangfang Zhong ◽  
Caishun Zhang ◽  
Wenbo Yang ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Energy Transfer Efficiency ◽  
Transfer Efficiency ◽  
Quantum Yields ◽  
Fluorescent Product ◽  
Triplet Energy ◽  
Fluorescence Quantum Yields ◽  
Triplet Energy Transfer ◽  
Triplet Triplet Annihilation

H2O2-activatable TTA upconversion was achieved with non-fluorescent 9,10-bis(diphenylphosphino)anthracene as a triplet acceptor/emitter, which can be oxidized to a fluorescent product by H2O2.

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.

Excitation and DE-Excitation of Yb3+ in Inp and Er3+ in Si: Photoluminescence and Impact Ionization Studies

1996 ◽  
Vol 422 ◽  
Author(s):  
T. Gregorkiewicz ◽  
I. Tsimperidis ◽  
C. A. J. Ammerlaan ◽  
F. P. Widdershoven ◽  
N. A. Sobolev
Keyword(s):  
Energy Transfer ◽  
Impact Ionization ◽  
Crystalline Silicon ◽  
Optical Excitation ◽  
Nonradiative Recombination ◽  
Energy Transfer Mechanism ◽  
Excitation Mechanism ◽  
Conduction Electrons ◽  
The One

AbstractIn the paper the existing information on the optical excitation of the erbium ion in crystalline silicon is critically reviewed. The proposed excitation mechanism is compared to the one which is believed to be responsible for the luminescence of ytterbium in indium phosphide. To this end the influence of constant and microwave electric field on the photoluminescence of both systems is inspected. It is shown that, although both systems show some similarities, their analogy is limited.The particular role of excitons and electrons in both the excitation as well as the de-excitation mechanism is investigated for the Si:Er system. The results of photoluminescence decay studies (T=4.2 K) are presented. It is argued that a nonradiative energy transfer to conduction electrons is responsible for the limitation of the energy transfer to the Er core and for its nonradiative recombination. Also, a prominent role of excitons in the energy transfer mechanism is confirmed. Finally, the origin of the 873 meV photoluminescence band recently reported in Er-implanted Si is discussed in relation to a possible defect-mediated activation of Er.

scholarly journals THE ROLE OF PHOSPHOCREATINE AND ADENOSINE-TRIPHOSPHATE IN MUSCULAR CONTRACTION

1953 ◽  
Vol 37 (1) ◽  
pp. 63-70 ◽  
Author(s):  
Emil Bozler
Keyword(s):  
Energy Transfer ◽  
Muscular Contraction ◽  
Energy Transfer Mechanism ◽  
Contracting Muscle ◽  
Low Concentrations ◽  
Strong Contraction ◽  
Autocatalytic Process ◽  
Ca Ions ◽  
Tension Curve

In the presence of 20 mM PC a strong contraction is produced in glycerol-extracted muscle fibers by ATP and AMP in concentrations as low as 10–6 M per liter. At low concentrations of nucleotide tension rises very slowly. This rise is interpreted as being due to absorption of nucleotide by the contractile elements. AMP gives an S-shaped tension curve, indicating that the conversion of AMP into ATP is an autocatalytic process. Tension is maintained in a contracted muscle even in PC solutions free of ATP. PC alone produces a contraction if applied within 5 minutes after ATP has been washed out from a contracting muscle. It is concluded from these results that PC is the substrate for the enzymatic activity of the contractile elements and that this activity depends on the presence of bound nucleotide which acts as an energy transfer mechanism. PC accelerates relaxation which is caused by ATP under certain conditions. In the presence of PC even very low concentrations of ATP can produce relaxation. A strong contraction can be produced under these conditions by the addition of Ca ions. These observations support the conclusion that relaxation depends on the rephosphorylation of nucleotide bound by the contractile elements.

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