Luminescence Quenching Research Articles

Quenching of luminescence by non-radiative tunnelling

Abstract It is demonstrated that the ensemble averaged radiative efficiency is given by the Laplace transform of averaged decay laws, which have been extensively studied in the field of energy transfer. This procedure leads to exact expressions, which include all neighbours, and which supersede Monte Carlo calculations for the efficiency.

Cathodoluminescence from deformed doped MgO crystals

Abstract The cathodoluminescence (CL) from indented Fe doped MgO single crystals has been studied with the scanning electron microscope and the results have been compared with the CL from undoped crystals. As in the undoped crystals, the iron doped crystals show in the deformed regions an enhanced luminescence emission but it has been found that iron acts as a quencher of luminescence. The results indicate that in the blue emission of the deformed crystals there is not a noticeable contribution of iron. From the evolution of CL with the irradiation time in the electron microscope it is concluded that the total Fe content influences the CL emission more than the Fe3+ content.

Quenching of luminescence by non-radiative tunnelling

Abstract In semiconductors at low temperatures, where thermal ionization is unlikely, the tunnelling of a carrier away from radiative centres (density p r) to non-radiative centres (density p n) provides an alternative luminescence quenching mechanism to thermal excitation into the band. It is argued that this may be a common quenching process in a variety of solid and liquid systems. When p r ≪ p n, an upper limit to the luminescence efficiency is given by a nearest-neighbour approximation. A lower limit is derived by a new many-neighbour approximation, and this is shown to be close to the exact value found by a Monte-Carlo simulation. The efficiency has also been calculated as p r approaches p n in the nearest-neighbour approximation, and it is shown to depend increasingly on tunnelling between nearest-neighbour radiative pairs.

Quenching of luminescence of dye adsorbates on hydrophobic silica gels by oxygen dissolved in water

Quenching of luminescence of dye adsorbates on hydrophobic silica gels by oxygen dissolved in water

The Synthesis and Luminescence Quenching of the Water-soluble Polymer-supported Tris(2,2′-bipyridine)ruthenium(II) Analogue

Abstract The p-aminostyrene-N-vinylpyrrolidone copolymer-supported tris(2,2′-bipyridine)ruthenium(II) analogue, [Ru(bpy)2(pbyCOOH)]2+ (bpy=2,2′-bipyridine and pbyCOOH=polymeric bipyridine ligand), has been prepared, and the luminescence behavior of the polymer complex has been investigated in an aqueous solution. The efficiency of the quenching of the excited state of the polymer complex with [Fe(CN)6]4−, [Co(phen)3]2+, and Cu2+ is compared with that of [Ru(bpy)3]2+. The quenching of the excited state of the polymer complex by Cu2+ is strongly enhanced by the effect of the polymer chains. In the polymer complex/Cu2+ system, the quenching by Cu2+ in the presence of poly(p-styrenesulfonate) is much more effective than in the absence of the polyion. The characteristics of the polymer complex in terms of the luminescence behavior are discussed.

Quenching of the charge transfer luminescence of tris(2,2′-bipyridine)Ru(II) by Co(III) ketoenolates

Quenching of the charge transfer luminescence of tris(2,2′-bipyridine)Ru(II) by Co(III) ketoenolates

Quenching of complex molecule luminescence by energy transfer under conditions of inhomogeneous level broadening

Quenching of complex molecule luminescence by energy transfer under conditions of inhomogeneous level broadening

Thermal Quenching of Luminescence in a Disordered Compound: EuNa2Mg2 ( VO 4 ) 3

Luminescence of is six times as bright as that of under 365 nm light excitation at room temperature, but it suffers from thermal quenching at higher temperatures. The quenching is mainly caused by non‐radiative relaxation from the emitting states. Energy diffusion among the lowest excited states, , to sinks is a main reason of relatively weak quenching below 500°K. At higher temperatures, drastic quenching due to nonradiative relaxation within each Eu3+ ion is observed. Disordered distribution of Eu3+and Na+ revealed by optical and powder x‐ray diffraction measurements is considered to induce the thermal quenching. Similar strong quenching beginning at around 500°–600°K is observed also for other disordered compounds, and .

Quenching of luminescence by electron transfer

It has been shown that quenching of the luminescence of ions in aqueous solution can occur by electron transfer. Attention is drawn to the fact that in solids a similar mechanism can be active.

Quenching of luminescence in semiconductors by charged defects

Charged point defects and dislocations create internal electric fields that can prevent the binding of carriers to luminescent centres such as N in GaP. The authors calculate the distribution of fields present in a semiconductor and its effect on the lifetime of an electron trapped at a localised impurity. The results show a decrease in the fraction of effective luminescent centres with increasing concentration of ionised donors and acceptors. Both unscreened dislocations and those with a compensating atmosphere of oppositely charged point defects are considered and the calculations show dark regions around them, as observed.

Quenching of Intrinsic Luminescence by Coloration in KI and RbI

The luminescence intensity measured under uv-excitation at low temperatures in X- irradiated KI and RbI has been compared with that measured in uncolored crystals. Reduction in the luminescence efficiency caused by the coloration is due to non-radiative annihilation of free excitons or conduction electron-hole pairs through interaction with V -centers. Change in the degree of the luminescence quenching observed with the increase in the photon energy of excitation from the exciton band region toward the interband transition region can be ascribed to the difference between the relaxation probability of excitons and of electron-hole pairs to the self-trapped exciton state. The temperature dependence of the luminescence quenching suggests that a part of free excitons relax to the self-trapped exciton state through thermal activation process

ChemInform Abstract: LUMINESCENCE QUENCHING OF DICYANOBIS(2,2′‐BIPYRIDINE)RUTHENIUM(II) AND DICYANOBIS(1,10‐PHENANTHROLINE)RUTHENIUM(II) BY TRANSITION METAL COMPLEXES

Chemischer InformationsdienstVolume 8, Issue 35 Physical Organic Chemistry ChemInform Abstract: LUMINESCENCE QUENCHING OF DICYANOBIS(2,2′-BIPYRIDINE)RUTHENIUM(II) AND DICYANOBIS(1,10-PHENANTHROLINE)RUTHENIUM(II) BY TRANSITION METAL COMPLEXES J. N. DEMAS, J. N. DEMASSearch for more papers by this authorJ. W. ADDINGTON, J. W. ADDINGTONSearch for more papers by this authorS. H. PETERSON, S. H. PETERSONSearch for more papers by this authorE. W. HARRIS, E. W. HARRISSearch for more papers by this author J. N. DEMAS, J. N. DEMASSearch for more papers by this authorJ. W. ADDINGTON, J. W. ADDINGTONSearch for more papers by this authorS. H. PETERSON, S. H. PETERSONSearch for more papers by this authorE. W. HARRIS, E. W. HARRISSearch for more papers by this author First published: August 30, 1977 https://doi.org/10.1002/chin.197735048AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume8, Issue35August 30, 1977 RelatedInformation

Quenching of luminescence and exciton diffusion in KI at low temperature

Exciton—defect interaction in KI between 4 and 77 K is measured through the study of the intrinsic luminescence of irradiated crystals excited by both u.v. and electron irradiation. Results are interpreted by a possible athermal diffusion of the non-relaxed exciton at low temperature.

Quenching of uranyl luminescence by water molecule

The limetime of uranyl luminescence was measured in aqueous solution. The quenching of uranyl luminescence by water molecules was satisfactorily interpreted by an electron transfer mechanism in terms of oxidation-reduction potentials of uranyl ion and water molecule. The proposed mechanism could also explain the variation in the luminescence lifetime (and the quenching rate constant) with change in pH of the uranyl solution and in the degree of formation of uranyl complex with fluoride, sulfate and phosphate anion.

Molecular oxygen enhanced fluorescence of organic molecules in polymer matrices: A singlet oxygen feedback mechanism

The surprising observation that molecular oxygen, the universal quencher of luminescence of organic molecules, can reverse its role and act as an enhancer of fluorescence in polymer matrices was originally recorded by Geacintov et al. Bolton, Kenner, and Khan investigated the phenomenon of oxygen enhanced fluoresence of organic molecules in polymer matrices and attributed the enhancement to a singlet oxygen feedback mechanism in which there is a repopulation of the singlet manifold of the organic molecule via energy transfer from singlet molecular oxygen. In this paper we examine the preliminary results and consider the relative merits of the singlet oxygen feedback mechanism and a trivial mechanism involving ground state depletion of the organic fluorescer in the evacuated samples. Optical cross beam experiments, designed to compare the extent of ground state depopulation of the organic molecule with the amount of enhancement observed, indicate that the depopulation mechanism can account for only a small part of the fluorescence enhancement. Furthermore, we report the discovery of oxygen stimulated fluorescence in similar systems under conditions in which the singlet manifold of the organic molecule can be populated only by energy transfer from singlet oxygen. Oxygen stimulated fluorescence is a direct and unequivocal confirmation of the basic idea of the singlet oxygen feedback mechanism and raises a fundamental question about the mechanism of oxygen quenching of the excited singlet states of organic molecules.

Influence of defects on the luminescence in KI

Quenching of exciton luminescence caused by coloration with u.v.-irradiation in KI and KI:Tl has been studied. Reduction in the luminescence intensity by coloration is found to depend on the coloration temperature as well as on the concentration of Tl + ions. Evidences are shown that the defects with which excitons interact are vacancies and V-centers.

Quenching of luminescence by coloration in KI and RbI

Quenching of exciton luminescence caused by coloration with u.v. irradiation in KI and RbI has been studied. Luminescence intensity measured after coloration is found to show a remarkable dependence on temperature. A possible explanation is given for the mechanism of luminescence quenching on the assumption that the luminescence intensity is proportional to the probability of exciton self-trapping.

Comments on the Article “On the Theory of Thermal Quenching of Luminescence” by H. Payen de la Garanderie and D. Curie

not Available.

Temperature Dependence of Non‐Linear Luminescence Quenching in Pyrene Crystals

Temperature Dependence of Non‐Linear Luminescence Quenching in Pyrene Crystals

Zur Fluoreszenzlöschung von organischen Einkristallen durch Röntgenbestrahlung

Quenching of luminescence upon irradiation with x-rays is investigated on the systems anthracene-tetracene, 2,3 dimethylnaphthalene-anthracene and 2,3 benzdiphenylenoxyd (Brasan)-tetracene. An annealing process is observed at the system anthracene-tetracene by tempering the samples at temperatures above 100 °C. From the temperature-dependence of luminescence some conclusions can be drawn concerning the irradiation-defects. It is possible to interpret the nonlinearity between quenching-effect and irradiated dose as a consequence of exciton-diffusion to the surface.