Relevant bibliographies by topics / Luminescence lifetime

Academic literature on the topic 'Luminescence lifetime'

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Published: 10 December 2022
Last updated: 29 January 2023

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Journal articles on the topic "Luminescence lifetime"

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Kang, Jie, Ai Ling Wang, Yan Rong Qu, Hai Bin Chu, and Yong Liang Zhao. "Preparation and Luminescent Property of EuxYy(TPTZ)2(POA)6 Complexes." Advanced Materials Research 1078 (December 2014): 118–21. http://dx.doi.org/10.4028/www.scientific.net/amr.1078.118.

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Using anion ligand phenoxyacetic acid (HPOA) and neutral ligand 2,4,6-tri(2-pyridyl)-s-triazine (TPTZ), a series of novel europium complexes EuxYy(TPTZ)2(POA)6·6H2O. The luminescence spectra, luminescence lifetimes and emission quantum efficiencies of the complexes were studied. The results show that doping appropriate amount of Y3+ can significantly increase the luminescence intensities, prolong the luminescent lifetime and improve the emission quantum efficiencies.
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de la Torre, Angel, Santiago Medina-Rodríguez, Jose C. Segura, and Jorge F. Fernández-Sánchez. "Self-Referenced Multifrequency Phase-Resolved Luminescence Spectroscopy." Sensors 20, no. 19 (September 24, 2020): 5482. http://dx.doi.org/10.3390/s20195482.

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Phase-resolved luminescence chemical sensors provide the analyte determination based on the estimation of the luminescence lifetime. The lifetime is estimated from an analysis of the amplitudes and/or phases of the excitation and emission signals at one or several modulation frequencies. This requires recording both the excitation signal (used to modulate the light source) and the emission signal (obtained from an optical transducer illuminated by the luminescent sensing phase). The excitation signal is conventionally used as reference, in order to obtain the modulation factor (the ratio between the emission and the excitation amplitudes) and/or the phase shift (the difference between the emission and the excitation phases) at each modulation frequency, which are used to estimate the luminescence lifetime. In this manuscript, we propose a new method providing the luminescence lifetimes (based either on amplitudes or phases) using only the emission signal (i.e., omitting the excitation signal in the procedure). We demonstrate that the luminescence lifetime can be derived from the emission signal when it contains at least two harmonics, because in this case the amplitude and phase of one of the harmonics can be used as reference. We present the theoretical formulation as well as an example of application to an oxygen measuring system. The proposed self-referenced lifetime estimation provides two practical advantages for luminescence chemical sensors. On one hand, it simplifies the instrument architecture, since only one analog-to-digital converter (for the emission signal) is necessary. On the other hand, the self-referenced estimation of the lifetime improves the robustness against degradation of the sensing phase or variations in the optical coupling, which reduces the recalibration requirements when the lifetimes are based on amplitudes.
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Waters, P. Dean, and David H. Burns. "Optimized Gated Detection for Lifetime Measurement over a Wide Range of Single Exponential Decays." Applied Spectroscopy 47, no. 1 (January 1993): 111–15. http://dx.doi.org/10.1366/0003702934048622.

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Optimal estimation parameters are determined for the rapid lifetime determination technique (RLD) of fitting an exponential model to luminescence decay data that exhibit a wide range of lifetimes. Optimization of the lifetime estimate by this technique depends on only two parameters—period of integration and separation between the periods of integration. Luminescence quenching experiments produce a range of decay lifetimes. Selection of a fixed set of measuring parameters to determine lifetime throughout the entire range can simplify instrumentation and result in enhanced computation speed. The measuring parameters must be optimized to yield the best estimation of each lifetime in the range. The errors in measured lifetime for the RLD technique are investigated for a wide range of luminescence decays. Optimal separation and periods of integration for the modified RLD technique are found by modeling a set of simulated decay data with different lifetimes. Results from the simulation are then compared to similar measurements of oxygen-quenched luminescence decay. Agreement between simulation and quenching data is good.
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Lis, Stefan, Slawomir But, Andrzej M. Klonkowski, and Beata Grobelna. "Spectroscopic studies of Ln(III) complexes with polyoxometalates in solids, and aqueous and non-aqueous solutions." International Journal of Photoenergy 5, no. 4 (2003): 233–38. http://dx.doi.org/10.1155/s1110662x03000370.

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Chosen polyoxometalate (POM) anions and their lanthanide(III) complexes, LnPOM, have been synthesized and spectroscopically characterized in solid state, aqueous and non-aqueous solutions. POMs, such as Keggin's, Dawson's and Anderson's type,Na9EuW10O36, compositions that function as inorganic cryptands ([(Na)P5W30O110]14−-Preyssler anion, and [(Na)As4W40O140]27−), containing inorganic(Na+,K+,NH4+)or organic (tetrabutylammonium,NBu4+) counter cations were obtained and their Ln(III) complexes (sandwiched and encapsulated) studied. The synthesized compounds were identified using elemental and thermogravimetric analysis, UV-Vis spectrophotometry and FTIR spectroscopy. The complexation studies were carried out with the use Nd(III) and Er(III) optical absorption and Eu(III) luminescence spectroscopy. Luminescence characterization, including results of intensity, quantum yields and luminescence lifetimes of EuPOM complexes in aqueous, non-aqueous solutions (DMF, DMSO, acetonitryle) and solid are discussed. Based on luminescence lifetime measurements of the Eu(III) ion the hydration numbers of its sandwiched (efficient emitters) and encrypted complexes have been determined and quenching effect discussed. The Eu(III) complexes entrapped in a xerogel matrix have been studied as luminescent materials. Luminescence intensity, lifetime and quantum yield of the EuPOM materials and their photochemical stability, during continuous UV irradiation, were tested.
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Lu, Kailei, Yingxin Yi, Li Xu, Xianhao Sun, Lu Liu, and Hanyang Li. "Temperature-Independent Lifetime and Thermometer Operated in a Biological Window of Upconverting NaErF4 Nanocrystals." Nanomaterials 10, no. 1 (December 20, 2019): 24. http://dx.doi.org/10.3390/nano10010024.

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Lifetime of lanthanide luminescence basically decreases with increasing the ambient temperature. In this work, we developed NaErF4 core–shell nanocrystals with compensation of the lifetime variation with temperature. Upconversion lifetime of various emissions remains substantially unchanged as increasing the ambient temperature, upon 980/1530 nm excitation. The concentrated dopants, leading to extremely strong interactions between them, are responsible for the unique temperature-independent lifetime. Besides, upconversion mechanisms of NaErF4 core-only and core–shell nanocrystals under 980 and 1530 nm excitations were comparatively investigated. On the basis of luminescent ratiometric method, we demonstrated the optical thermometry using non-thermally coupled 4F9/2 and 4I9/2 emissions upon 1530 nm excitation, favoring the temperature monitoring in vivo due to both excitation and emissions fall in the biological window. The formed NaErF4 core–shell nanocrystals with ultra-small particle size, highly efficient upconversion luminescence, unique temperature-independent lifetimes, and thermometry operated in a biological window, are versatile in applications such as anti-counterfeiting, time-domain manipulation, and biological thermal probes.
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Gonzalez-Garcia, M. Carmen, Pilar Herrero-Foncubierta, Emilio Garcia-Fernandez, and Angel Orte. "Building Accurate Intracellular Polarity Maps through Multiparametric Microscopy." Methods and Protocols 3, no. 4 (November 11, 2020): 78. http://dx.doi.org/10.3390/mps3040078.

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The precise knowledge of intracellular polarity, a physiological parameter that involves complex and intertwined intracellular mechanisms, may be relevant in the study of important diseases like cancer or Alzheimer’s. In this technical note, we illustrate our recently developed, accurate method for obtaining intracellular polarity maps employing potent fluorescence microscopy techniques. Our method is based on the selection of appropriate luminescent probes, in which several emission properties vary with microenvironment polarity, specifically spectral shifts and luminescence lifetime. A multilinear calibration is performed, correlating polarity vs. spectral shift vs. luminescence lifetime, to generate a powerful and error-free 3D space for reliable interpolation of microscopy data. Multidimensional luminescence microscopy is then used to obtain simultaneously spectral shift and luminescence lifetime images, which are then interpolated in the 3D calibration space, resulting in accurate, quantitative polarity maps.
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Kühl, Michael, Lars F. Rickelt, and Roland Thar. "Combined Imaging of Bacteria and Oxygen in Biofilms." Applied and Environmental Microbiology 73, no. 19 (August 17, 2007): 6289–95. http://dx.doi.org/10.1128/aem.01574-07.

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ABSTRACT Transparent sensors for microscopic O2 imaging were developed by spin coating an ultrathin (<1- to 2-μm) layer of a luminescent O2 indicator onto coverslips. The sensors showed (i) an ideal Stern-Volmer quenching behavior of the luminescence lifetime towards O2 levels, (ii) homogeneous measuring characteristics over the sensor surface, and (iii) a linear decline of luminescence lifetime with increasing temperature. When a batch of such coverslip sensors has been characterized, their use is thus essentially calibration free at a known temperature. The sensors are easy to use in flow chambers and other growth devices used in microbiology. We present the first application for combined imaging of O2 and bacteria in a biofilm flow chamber mounted on a microscope equipped with a spinning-disk confocal unit and a luminescence lifetime camera system.
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Egami, Yasuhiro, Yuya Yamazaki, Naoto Hori, Yosuke Sugioka, and Kazuyuki Nakakita. "Investigation of Factors Causing Nonuniformity in Luminescence Lifetime of Fast-Responding Pressure-Sensitive Paints." Sensors 21, no. 18 (September 10, 2021): 6076. http://dx.doi.org/10.3390/s21186076.

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Factors that cause nonuniformity in the luminescence lifetime of pressure-sensitive paints (PSPs) were investigated. The lifetime imaging method of PSP does not theoretically require wind-off reference images. Therefore, it can improve measurement accuracy because it can eliminate errors caused by the deformation or movement of the model during the measurement. However, it is reported that the luminescence lifetime of PSP is not uniform on the model, even under uniform conditions of pressure and temperature. Therefore, reference images are used to compensate for the nonuniformity of the luminescence lifetime, which significantly diminishes the advantages of the lifetime imaging method. In particular, fast-responding PSPs show considerable variation in luminescence lifetime compared to conventional polymer-based PSPs. Therefore, this study investigated and discussed the factors causing the nonuniformity of the luminescence lifetime, such as the luminophore solvent, luminophore concentrations, binder thickness, and spraying conditions. The results obtained suggest that the nonuniformity of the luminophore distribution in the binder caused by the various factors mentioned above during the coating process is closely related to the nonuniformity of the luminescence lifetime. For example, when the thickness of the binder became thinner than 8 μm, the fast-responding PSPs showed a tendency to vary significantly in the luminescence lifetime. In addition, it was found that the luminescence lifetime of fast-responding PSP could be changed in the depth direction of the binder depending on the coating conditions. Therefore, it is important to distribute the luminophore uniformly in the binder layer to create PSPs with a more uniform luminescence lifetime distribution.
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Jung, Euo Chang, Yongheum Jo, Tae-Hyeong Kim, Hee-Kyung Kim, Hye-Ryun Cho, Wansik Cha, Min Hoon Baik, and Jong-Il Yun. "Surface Coverage- and Excitation Laser Wavelength-Dependent Luminescence Properties of U(VI) Species Adsorbed on Amorphous SiO2." Minerals 12, no. 2 (February 10, 2022): 230. http://dx.doi.org/10.3390/min12020230.

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Time-resolved luminescence spectroscopy is usefully used to identify U(VI) surface species adsorbed on SiO2. However, the cause of the inconsistent luminescence lifetimes and spectral shapes reported previously remains undetermined. In this study, the U(VI) surface coverage (Γ) and excitation laser wavelength (λex) were examined as the predominant factors governing the luminescence properties of U(VI) surface species. At neutral pH, the luminescence lifetimes of U(VI) surface species increased with decreasing Γ. In the low-Γ region, where a relatively large number of adjacent surface sites are involved in the formation of multidentate surface complexes, the displacement of more number of coordinated water molecules in the equatorial plane of U(VI) results in a longer lifetime. The pH-dependent luminescence lifetimes of U(VI) surface species at the same U(VI) to SiO2 concentration ratio in the pH range of 4.5–7.5 also explain the effect of the surface binding sites on the luminescence lifetime. The time-resolved luminescence properties of the U(VI) surface species were also investigated at different excitation wavelengths. Continued irradiation of the SiO2 surface with a UV laser beam at λex = 266 nm considerably reduced the luminescence intensities of the U(VI) surface species. The higher the laser pulse energy, the greater the decrease in luminescence intensity. Laser-induced thermal desorption (LITD) of U(VI) surface species is suggested to be the origin of the decrease in luminescence intensity. LITD effects were not observed at λex = 355 and 422 nm, even at high laser pulse energies.
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Zhao, Zhihuan, Yao Wang, Haoyang Jiang, Jixian Liu, Linjun Huang, Yanna Zhang, Yanqi Wang, Laurence A. Belfiore, and Jianguo Tang. "Optical Features of Lanthanide Luminescent Hydrogel Based on Polyethylene Glycol with Silica Nanoparticles." Science of Advanced Materials 13, no. 1 (January 1, 2021): 123–30. http://dx.doi.org/10.1166/sam.2021.3850.

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Inorganic/polymer hybrid hydrogels generally exhibit excellent mechanical properties, while extra function include luminescence are extremely explored due to the further application in sensors and optoelectronic devices. Herein, we report the rare-earth (RE) complex/silica nanoparticles (SNs) luminescent hybrid polyethylene glycol (PEG) hydrogels showing stable luminescence. The hybrid hydrogels coordinated with RE (Eu3+) complex are fabricated via a convenient in situ photocrosslinked procedure. The coordination polymers showed red luminescent color under the 365 nm UV irradiation. Furthermore, the hybrid hydrogel exhibited long luminescence lifetime. These properties of hybrid luminescent hydrogel gave rise to a great improvement in the potential applications as a soft material.
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Dissertations / Theses on the topic "Luminescence lifetime"

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Ramshesh, Venkat K. Lemasters John J. "Luminescence lifetime imaging microscopy by confocal pinhole shifting LLIM-CPS." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2007. http://dc.lib.unc.edu/u?/etd,1968.

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Thesis (Ph. D.)--University of North Carolina at Chapel Hill, 2007.
Title from electronic title page (viewed Dec. 11, 2008). "... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Biomedical Engineering." Discipline: Biomedical Engineering; Department/School: Medicine.
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Kage, Daniel. "Studies on fluorophore-loaded polymer microbeads and luminescence lifetime encoding in flow cytometry." Doctoral thesis, Humboldt-Universität zu Berlin, 2019. http://dx.doi.org/10.18452/20608.

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Die Dissertation umfasst zwei Themenblöcke: Zum einen wurden die optisch-spektroskopischen Eigenschaften von fluoreszenten, farbstoffbeladenen Polymer-Mikropartikeln untersucht. Zum anderen wurde die Anwendbarkeit solcher Partikel für die Lumineszenzlebensdauer-Kodierung in der Durchflusszytometrie evaluiert. Die Charakterisierung der farbstoffbeladenen Mikropartikel erfolgte mittels optischer Spektroskopie. Am Beispiel mit Rhodamin 6G beladener Polymethylmethacrylat-Partikel konnte ein besseres Verständnis des Einbaus der Farbstoffmoleküle und der resultierenden Fluoreszenz-Charakteristika gewonnen werden. Es stellte sich heraus, dass die Beladungseffizienz stark vom mittleren Partikeldurchmesser und den Synthesebedingungen abhängt. In Verbindung mit den beobachteten optisch-spektroskopischen Eigenschaften wurde geschlussfolgert, dass sich eine farbstoffreiche Schicht an der Oberfläche der Partikel bildet, die sich wesentlich von den sterisch eingebauten Farbstoffmoleküle im Partikelvolumen unterscheidet. Hohe Farbstoffkonzentrationen in dieser Oberflächenschicht führen vermutlich zu Aggregation. Des Weiteren deuten Veränderungen der Fluoreszenzeigenschaften auf intrapartikuläre Energiewanderung bei zunehmender Farbstoffkonzentration hin. Diese Interpretation der experimentellen Ergebnisse konnte qualitativ durch einen Algorithmus zur Simulation der Energiewanderung bestätigt werden. Die Anwendbarkeit der Lumineszenzlebensdauer als Kodierungsparameter in der Zeitdomäne konnte unter Verwendung eines Durchflusszytometer-Prototypen analysiert werden. Die wohl größte Herausforderung bei der Lebensdauermessung in der Durchflusszytometrie ist die kurze Interaktionszeit zwischen Objekt und Anregungslicht. Synthetische Daten wurden herangezogen, um den Einfluss einzelner Messparameter und -bedingungen unabhängig voneinander abzuschätzen. Es konnte festgestellt werden, dass die Lumineszenzlebensdauer als Kodierungsparameter in der Zeitdomäne prinzipiell zugänglich ist.
This thesis comprises two main topics. First, the optical-spectroscopic properties of fluorescent microbeads loaded with organic dyes were studied. In the second part, the feasibility of time-domain luminescence lifetime encoding in flow cytometry based on such microbeads was assessed. The study of the dye-loaded polymer microbeads was based on optical spectroscopy. Poly(methyl methacrylate) beads loaded with rhodamine 6G were used as an example system to achieve a better understanding of the dye incorporation procedure. The dye loading efficiency turned out to be strongly dependent on the mean diameter of the beads and on the amounts of certain compounds used for the bead synthesis. In correlation with the observed fluorescence characteristics, it was deduced that a layer with high local dye concentration forms around each bead. The properties of this layer substantially differ from those of the sterically incorporated dye molecules in the bead core. The high dye concentration in this layer results in aggregation accompanied by the respective changes of the fluorescence characteristics of the beads. Moreover, the observed changes in fluorescence properties indicated the existence of an intra-particulate energy migration process at increased dye loading concentrations. A simulation of the energy migration process based on a random walk algorithm confirmed the interpretation of the experimental results. For the assessment of luminescence lifetime encoding in time-domain flow cytometry, a prototype setup was used. The main issue of lifetime determination in flow cytometry is represented by the short interaction time of only tens of microseconds of the objects with the excitation light spot. Synthetic data were used to study certain measurement parameters and conditions as well as the data analysis procedure independently of other influences. As a result, luminescence lifetime is generally applicable as an encoding parameter in time-domain flow cytometry.
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Coyle, Lisa M. "Lifetime measurements on pressure sensitive paints : temperature correction, effects of environment, and trials on new luminescent materials /." Thesis, Connect to this title online; UW restricted, 1999. http://hdl.handle.net/1773/8698.

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El, Mouedden Yamna. "Lifetime and efficiency improvement of organic luminescent solar concentrators for photovoltaic applications." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2016. https://ro.ecu.edu.au/theses/1779.

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In order to achieve the goal of zero net-energy consumption in residential and commercial buildings, substantial research has been devoted to developing methods for energy harvesting from window glass that is capable of passing visible light through the windows of buildings while converting the unwanted invisible solar radiation into electricity. Research has focussed on two particular aspects, namely (i) the integration of thin-film technology for solar radiation transmission control and (ii) light guiding structures for solar radiation routing towards the edges of the glass window. Recently, photovoltaic (PV) solar cells have been investigated and promoted as products for converting solar energy into electricity. Due to the increased demand for renewable energy sources, the manufacture of PV panels’ arrays has advanced considerably. However, they cannot compete with fossil fuel or nuclear energy, due to the high cost of inorganic solar cells and their low power conversion efficiency (PCE). To lower the cost per installed capacity ($/Watt) and to use the complete solar spectrum, new PV technologies have been developed, such as solar concentrators. Among the many kinds of concentrators, luminescent solar concentrators (LSCs) have significant industry application potential. Materials used in LSCs are inexpensive, the solar cell size is reduced and no tracking of the sun is required. In an LSC, the incident sunlight is absorbed by luminescent species, such as fluorescent dyes, quantum dots or rare-earth ion embedded in the active layer (organic or inorganic), which re-emits light in random directions usually at longer wavelengths. In an ideal LSC, all the re-emitted light can be routed towards the edges, where the attached small-area solar cells harvest the light and convert it into electricity. In this thesis, several contributions are made toward the development of organic LSCs. The first contribution is related to the design and development of multilayer thin film structures containing dielectric and metal layers, using physical vapour deposition, for the control of thermal and solar radiation propagated through glass windows. Measured transmittance spectra for the developed thin-film structures are in excellent agreement with simulation results. For the second contribution, a cost-effective, long-life-time organic LSC device with UV epoxy as a waveguide layer doped by two organic materials is developed. A PCE as high as 5.3% and a device lifetime exceeding 1.0×105 hrs are experimentally achieved. The third contribution of the thesis is the development of a general method for encapsulating organic LSCs, based on employing three optically transparent layers, (i) an encapsulating epoxy layer and (ii) two insulating SiO2 layers that prevent the dye dissolving into the epoxy layer. The encapsulated organic LSCs demonstrate an ultra-long lifetime of ~ 3.0×104 hrs and 60% transparency when operated in an ambient environment, of around 5 times longer than that of organic LSCs without encapsulation. Finally, the last contribution of the thesis is the development of a new LSC architecture that mitigates the reabsorption loss typically encountered in LSCs. Experimental results demonstrate significant reduction in photon reabsorption, leading to a 21% increase in PCE, in comparison with conventional LSCs.
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Kage, Daniel [Verfasser], Stefan [Gutachter] Kirstein, Oliver [Gutachter] Benson, and Michael [Gutachter] Kumke. "Studies on fluorophore-loaded polymer microbeads and luminescence lifetime encoding in flow cytometry / Daniel Kage ; Gutachter: Stefan Kirstein, Oliver Benson, Michael Kumke." Berlin : Humboldt-Universität zu Berlin, 2019. http://d-nb.info/1198207000/34.

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Mihalcescu, Irina. "Analyse temporelle des mécanismes de luminescence du silicium poreux." Université Joseph Fourier (Grenoble ; 1971-2015), 1994. http://www.theses.fr/1994GRE10210.

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Dans ce travail, nous avons etudie certains aspects du mecanisme de la luminescence du silicium poreux. La particularite de l'approche a ete le suivi simultane de l'intensite, des temps de vie et de la forme du declin de la pl en fonction des plusieurs parametres tels que: la temperature, le niveau d'oxydation anodique et l'intensite d'excitation. Nous decrivons la structure poreuse comme un ensemble de cristallites de dimensions nanometriques, interconnectees par des ponts de silicium ou de silice. Le premier niveau excite dans ces cristallites est localise, les porteurs se retrouvant confines dans un point quantique. Par contre, les niveaux excites superieurs sont etendus sur plusieurs cristallites, les porteurs etant confines dans un fil quantique. Pour des temperatures plus petites que 250k, nous avons conclu que les porteurs sont localises et une description de la dynamique de recombinaison limitee par l'effet tunnel est valable dans toute cette gamme des temperatures. A plus hautes temperatures, le changement de la forme du declin et la forte decroissance de l'intensite de la pl ont ete associes a une delocalisation progressive des porteurs par activation thermique. Dans ce cadre, l'evolution contraire, enregistree au cours de l'oxydation anodique du silicium poreux, est assimilee a une localisation progressive des porteurs par l'accroissement des barrieres de potentiel du a l'oxydation des ponts reliant les cristallites. Le dernier volet de ce travail comporte une etude de l'evolution de l'intensite de la pl en fonction de l'intensite d'excitation. La saturation de la pl, detectee dans un regime de fortes intensites d'excitation, a ete attribuee a une intensification de la recombinaison auger. La meme explication est ensuite utilisee pour justifier la diminution du rendement de luminescence dans un regime de forte injection electrique
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Gouin, Jean-François. "Fluoro-capteur à fibres optiques pour le dosage de l'oxygène en milieu marin." Vandoeuvre-les-Nancy, INPL, 1996. http://www.theses.fr/1996INPL127N.

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Parce qu'ils offrent de nombreux avantages par rapport aux méthodes classiques de mesure, les capteurs chimiques optiques, ou optodes, connaissent un large succès depuis une quinzaine d'années. De nombreux analytes peuvent être dosés par ces méthodes. Comme il prend part à beaucoup de phénomènes chimiques et biochimiques, l'oxygène est l'un des plus souvent cité. La mesure est fondée sur l'inhibition, par l'oxygène, de la fluorescence d'un indicateur. La connaissance de l'intensité ou plutôt de la durée de vie de fluorescence permet de déterminer la concentration en oxygène autour de l'indicateur placé à l'extrémité d'une ou plusieurs fibres optiques. Nous nous sommes intéressés à l'application de cette nouvelle voie de mesure au milieu marin. Après avoir mis au point et caractérisé un dispositif de mesure de durée de vie de fluorescence, deux composés fluorescents ont été étudiés: le pyrène et le tris(1,10-phénantroline)ruthenium(ii) chloride hydrate. La calibration en fonction de l'oxygène a été effectuée et pour le second composé, qui s'est révélé plus performant, les influences de la température, de la salinité et de la pression hydrostatique ont été étudiées
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Khalid, Ashiq Hussain. "Development of phosphor thermometry systems for use in development gas turbine engines." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/development-of-phosphor-thermometry-systems-for-use-in-development-gas-turbine-engines(f01316f9-4622-4a6d-b2d0-611a9191b5eb).html.

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The pursuit for improved engine efficiency is driving the demand for accurate temperature measurement inside turbine engines. Accurate measurement can allow engines to be operated closer to their design limits to improve thermal efficiency. It can enable engineers to verify mechanical integrity, provide better prediction of component life, validate CFD and other design tools and aid the development for leaner more efficient engines. Unfortunately, experimentally measuring surface temperatures under harsh rotating conditions is challenging. This EngD study conducted by Ashiq Hussain Khalid at the University of Manchester and Rolls-Royce plc, reviews the rationale of using phosphor thermometry over existing methods, including thermocouples, pyrometry and thermal paints/melts, which lack detail, accuracy, or are too expensive for continuous testing. Although phosphor thermometry exhibits desirable characteristics, the high temperature and fast rotating engine environment presents some challenges that would need to be addressed before a successful measurement system can be implemented. Examples of such issues include: rising blackbody radiation, restricted optical access, fibre optic constraints and limited time period to collect data. These factors will impose measurement limits and greatly influence the design philosophy of the system, including phosphor choice, phosphor lifetime characteristics, bonding technique, excitation/detection methodologies and probe design. Taking these into consideration, the research focuses on the development of phosphor thermometry systems for use in development gas turbine engines, with measurement solutions for specific engine components. The high pressure turbine blade was given research priority. A number of phosphors including YAG:Tb, YAG:Tm. Y2O3:Eu and Mg3F2GeO4:Mn were investigated and characterised in terms of intensity and lifetime decay, with increasing temperature up to 1500oC. Spectral analysis and absolute intensity measurements established emission peaks and permitted comparative quantitative analysis to optimise system setup. The intensity of phosphor emission relative to Planck's blackbody radiation was also performed. YAG:Tm under 355nm illumination was found to exhibit the highest emission intensity at high temperatures, and because its spectral emission peak at 458nm was the lowest, its advantage in terms of blackbody radiation was further amplified. For rotating components, an upper temperature limit is reached based on the emission intensity at rising blackbody radiation levels and the system's ability to detect fast decays. A lower limit is reached based on the quenching temperature, probe design and rotational velocity. There are different methods to correct the distorted decay waveform as it traverses through the acceptance cone of the fibre. A phosphor selection criterion, taking into consideration these limitations, was successfully applied for various rotating engine components. The optical layout was setup and tested on stationary and rotating cases under laboratory conditions using similar design constraints, including fibre choice, maximum permissible lens size and target distances. A series of tests validated design methodologies and assumptions to enable testing on full scale rotating engine components. Mg3F2GeO4:Mn, using 355nm illumination, was found to be the most suitable phosphor for the HP drive cone. The estimated performance under the expected rotational speeds was found to be 624-812°C with a standard uncertainty of ±0.99%. YAG:Tm, illuminated with 355nm, was found to be the most promising phosphor for high pressure turbine blade measurements. The performance under the expected rotational speeds was found to be 1117-1375°C with a standard uncertainty of ±0.97%. This is better than other competing technologies that are currently available for temperature measurement of rotating turbine blades.
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Ring, Josh. "Novel fabrication and testing of light confinement devices." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/novel-fabrication-and-testing-of-light-confinement-devices(51572720-0c49-482e-8523-e44ca877117f).html.

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The goal of this project is to study novel nanoscale excitation volumes, sensitive enoughto study individual chromophores and go on to study new and exciting self assemblyapproaches to this problem. Small excitation volumes may be engineered using light con-finement inside apertures in metal films. These apertures enhance fluorescence emissionrates, quantum yields, decrease fluorescence quenching, enable higher signal-to-noiseratios and allow higher concentration single chromophore fluorescence, to be studied byrestricting this excitation volume. Excitation volumes are reported on using the chro-mophore's fluorescence by utilising fluorescence correlation spectroscopy, which monitorsfluctuations in fluorescence intensity. From the correlation in time, we can find the res-idence time, the number of chromophores, the volume in which they are diffusing andtherefore the fluorescence emission efficiency. Fluorescence properties are a probe ofthe local environment, a particularly powerful tool due to the high brightness (quantumyield) fluorescent dyes and sensitive photo-detection equipment both of which are readilyavailable, (such as avalanche photodiodes and photomultiplier tubes). Novel materialscombining the properties of conducting and non-conducting materials at scales muchsmaller than the incident wavelength are known as meta-materials. These allow combi-nations of properties not usually possible in natural materials at optical frequencies. Theproperties reported so far include; negative refraction, negative phase velocity, fluorescenceemission enhancement, lensing and therefore light confinement has also been proposed tobe possible. Instead of expensive and slow lithography methods many of these materialsmay be fabricated with self assembly techniques, which are truly nanoscopic and otherwiseinaccessible with even the most sophisticated equipment. It was found that nanoscaled volumes from ZMW and HMMs based on NW arrays wereall inefficient at enhancing fluorescence. The primary cause was the reduced fluorescencelifetime reducing the fluorescence efficiency, which runs contrary to some commentatorsin the literature. NW based lensing was found to possible in the blue region of the opticalspectrum in a HMM, without the background fluorescence normally associated with a PAAtemplate. This was achieved using a pseudo-ordered array of relatively large nanowireswith a period just smaller than lambda / 2 which minimised losses. Nanowires in the traditionalregime lambda / 10 produced significant scattering and lead to diffraction, such that they werewholly unsuitable for an optical lensing application.
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Victoria, Rosemary. "Development of luminescent ruthenium complexes for in-vitro fluorescence imaging of angiogenesis with the RGD peptide." Honors in the Major Thesis, University of Central Florida, 2012. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/633.

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Herein we report the synthesis of an RGD-ruthenium bipyridine [Ru(Bpy)2(BpyRGD)]2+ complex aimed at the detection of angiogenesis. Angiogenesis plays a critical role in many pathophysiological processes, such as tumor growth. The αv-integrins (αv[beta]3, αv[beta]5) are currently used as molecular targeting sites for anti-angiogenic therapies. The [Ru(Bpy)2(BpyRGD)]2+ complex is an organometallic luminescent probe, which enables noninvasive, in vitro imaging of αv[beta]3 expression. Peptides containing the arginine-glycine-aspartic acid (RGD) sequence have been shown to bind strongly to the αvb3 integrin. The RuBpy probes are soluble in water, display long lifetimes, and are photochemically stable. These properties enable the Ru(tris-bpy) complexes to be useful in numerous applications in biophysical and cell biology. The [Ru(Bpy)2(BpyRGD)]2+ complex was synthesized by combining the succinimidyl ester on the RuBpy complex with the lysine of the c(RGDfK) peptide. The results of the one-photon fluorescence bioimaging showed selective binding of the cyclic RGD to αv[beta]3 integrin, which supports previous literature. The high luminescence intensity, long lifetimes, and low cell toxicity levels of dye [Ru(Bpy)2(BpyRGD)]2+, illustrates the potential usage of this probe for future biological applications.
B.S.
Bachelors
Sciences
Biology
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Books on the topic "Luminescence lifetime"

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Dattani, Roni S. A luminescence - lifetime based O2 sensor for tissue culture applications. Ottawa: National Library of Canada, 2002.

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Book chapters on the topic "Luminescence lifetime"

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Wang, P. W., R. F. Haglund, L. T. Hudson, D. L. Kinser, M. H. Mendenhall, N. H. Tolk, and R. A. Weeks. "Long Lifetime of Bulk Luminescence Observed in Spectrosil Glasses Under Electron Bombardment." In Desorption Induced by Electronic Transitions DIET III, 289–94. Berlin, Heidelberg: Springer Berlin Heidelberg, 1988. http://dx.doi.org/10.1007/978-3-642-73728-2_43.

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Huntosova, Veronika, and Georges Wagnieres. "CHAPTER 15. pO2 Measurements in Biological Tissues by Luminescence Lifetime Spectroscopy: Strategies to Exploit or Minimize Phototoxic Effects in Tumors." In Quenched-phosphorescence Detection of Molecular Oxygen, 298–318. Cambridge: Royal Society of Chemistry, 2018. http://dx.doi.org/10.1039/9781788013451-00298.

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Nwaigwe, Casmiar I., Marcie A. Roche, Oleg Grinberg, and Jeff F. Dunn. "Brain Tissue and Sagittal Sinus pO2 Measurements Using the Lifetimes of Oxygen-Quenched Luminescence of a Ruthenium Compound." In Oxygen Transport to Tissue XXIV, 101–11. Boston, MA: Springer US, 2003. http://dx.doi.org/10.1007/978-1-4615-0075-9_10.

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Papkovsky, Dmitry B. "Biosensors on the Basis of Luminescence Lifetime Based Oxygen Sensor." In Biosensors '94, 235. Elsevier, 1994. http://dx.doi.org/10.1016/b978-1-85617-242-4.50193-2.

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Bradrick, Thomas D., and Jorge E. Churchich. "Time-resolved fluorescence and phosphorescence spectroscopy." In Spectrophotometry and Spectrofluorimetry. Oxford University Press, 2000. http://dx.doi.org/10.1093/oso/9780199638130.003.0007.

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In this chapter, we outline the basic theory and methodology for making time resolved fluorescence and phosphorescence measurements. We begin with a brief discussion of the intrinsic time dependence of fluorescence and phosphorescence decays, and also introduce several important photophysical concepts. Energy transfer measurements, which are important for determining molecular distances, are then addressed, followed by the convolution integral (which describes the luminescence decay that is actually observed in pulsed excitation experiments) and the relationships that are used to determine fluorescence lifetimes from phase/modulation data. Polarized fluorescence measurements, which are an important tool for following molecular motions, are then discussed, and the fluorescence portion of the chapter concludes with an overview of data analysis and brief descriptions of the instrumentation that is used in making time-resolved fluorescence measurements. The remainder of the chapter is then devoted to a discussion of phosphorescence spectroscopy. The intrinsic time dependence of fluorescence decays is derived in Section 3.3 of Chapter 2. There it is shown that if a population of excited singlet-state molecules is generated instantaneously, its size decreases exponentially with time, as does the intensity of the emitted photons. The fluorescence lifetime τS is typically used to describe the rate of decay, where τs-1 = kR + kNR + kISC + kPR and kR, kNR, kISC and kpR are the rate constants for the various parallel unimolecular de-excitation processes. If there are several non-interacting fluorophore species in solution, their excited states will decay independently and a sum of exponentials will be needed to describe how the sample’s fluorescence intensity decreases with time.
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Chithambo, Makaiko L. "Temperature dependent effects of luminescence lifetimes." In An Introduction to Time-Resolved Optically Stimulated Luminescence. IOP Publishing, 2018. http://dx.doi.org/10.1088/2053-2571/aae5dach4.

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Ramya, Emusani. "Green Synthesis of Metal Nanostructures and Its Nonlinear Optical Properties." In Nonlinear Optics [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.99449.

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Simple green synthesis of metal nanoparticles (Ag NPs) was prepared by using Raphanussativus leaf extract. This extract acts as reduce and stabilizing agent. The formation of silver NPs was confirmed and characterized by XRD, UV–visible absorption spectrum, TEM, and FTIR. The luminescence enhancement and quenching of Eu3+and Sm3+ ions were observed in the presence of silver NPs. The luminescence enhancement is owing to arise in the electric-dipole transition with alteration of the field around Ln3+ ions. Nonlinear studies in femtosecond (fs) and picosecond (ps) time scales have been studied by using the Z-scan technique. Third-order nonlinear optical susceptibility of silver nanoparticles was obtained with Degenerate Four-Wave Mixing (DFWM) in the fs regime. The lifetimes of lanthanum complexes were increased by the concentration of silver NPs and decreased for further silver. The high enhanced luminescence and nonlinear studies of green synthesized silver nanoparticles can be used in optics and bio applications.
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GADELLA, THEODORUS W. J. "Fluorescence Lifetime Imaging Microscopy (FLIM): Instrumentation and Applications." In Fluorescent and Luminescent Probes for Biological Activity, 467–79. Elsevier, 1999. http://dx.doi.org/10.1016/b978-012447836-7/50036-1.

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"Long-Lifetime Luminescent Nanobioprobes for Advanced Cytometry Biosensing." In Nanotechnology in Australia, 333–62. Jenny Stanford Publishing, 2011. http://dx.doi.org/10.1201/b11034-12.

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Kumar, Pramod, and Sushil Kumar. "Detection of Bio-Relevant Metal Ions by Luminescent Ru(II)-Polypyridyl Based Sensors." In Ruthenium - an Element Loved by Researchers [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.96453.

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Biorelevant metal ions such as Cu2+ and Fe2+/Fe3+ participate in various biological events which include electron transfer reactions, delivery and uptake of oxygen, DNA and RNA syntheses, and enzymatic catalysis to maintain fundamental physiological processes in living organisms. So far, several analytical techniques have been investigated for their precise detection; however, luminescence-based sensing is often superior due to its high sensitivity, selectivity, fast and easy operation and convenient cellular imaging. Owing to their immense photophysical and photochemical properties stemming from large Stokes shift, absorption in visible region, good photostability and long excited state lifetimes, Ru(II)-polypyridyl-based complexes have gained increasing interest as luminophores. Over past few decades, several Ru(II)-polypyridyl based chemosensors have rapidly been developed for detection of different biorelevant and other metal ions. The main object of this book chapter is to cover a majority of Ru(II)-polypyridyl based chemosensors showing a selective and sensitive detection of bio-relevant Cu2+ and Fe2+/Fe3+ ions. The photophysical properties of Ru(II) complexes, detection of metal ions, sensing mechanism and applications of these sensors are discussed at a length.
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Conference papers on the topic "Luminescence lifetime"

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Deng, Qisheng, Zece Zhu, and Xuewen Shu. "Auto-phase-locked Time-gated Luminescence Detection System for Spectrally Resolved Luminescence Lifetime Detection." In Frontiers in Optics. Washington, D.C.: OSA, 2020. http://dx.doi.org/10.1364/fio.2020.jtu1a.2.

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Jia, Jianguo, Nima Sayyadi, Yan Wang, Honghua Hu, Karen Vickery, and Yiqing Lu. "Lifetime-Multiplexed Luminescence in situ Hybridisation for Bacteria Detection." In Conference on Lasers and Electro-Optics/Pacific Rim. Washington, D.C.: OSA, 2020. http://dx.doi.org/10.1364/cleopr.2020.p3_10.

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Orellana, Guillermo, Cesar de Dios, Maria C. Moreno-Bondi, and Maria D. Marazuela. "Intensity- and lifetime-based luminescence optosensing of carbon dioxide." In European Symposium on Optics for Environmental and Public Safety, edited by Annamaria V. Scheggi. SPIE, 1995. http://dx.doi.org/10.1117/12.221729.

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Dianov, E. M., V. M. Mashinsky, V. B. Neustruev, O. D. Sazhin, and V. A. Sidorov. "Rise and Decay of 3.15 eV Luminescence in Germanosilicate Glass: Influence of Glass Densification." In Bragg Gratings, Photosensitivity, and Poling in Glass Fibers and Waveguides. Washington, D.C.: Optica Publishing Group, 1997. http://dx.doi.org/10.1364/bgppf.1997.jmf.3.

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A wide variety of defects in germanosilicate glass observed in absorption and in luminescence spectra results in the energy transfer from some defects to others. Such a process was directly demonstrated by Gallagher and Osterberg1 and Bagratashvili et al.2 when 3.15 eV luminescence of germanium oxygen-deficient center (GODC) was excited by 5 eV photons. Along with usually observed decay of luminescence with about 100 µs lifetime they observed an initial rise of the luminescence with time of about 10 µs. To explain this phenomenon, Gallagher and Osterberg added to the commonly accepted scheme of GODC’s states (S0, S1 and T1) one more energy state of another defect. This state can nonradiatively transfer its excitation to the triplet state of GODC and this results in the rise of triplet-to-singlet luminescence. In this case the rate of the rise is governed by the lifetime of additional state.
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Batarseh, Mahed, Zhean Shen, and Aristide Dogariu. "Delayed luminescence from mesoscopic scattering media." In CLEO: QELS_Fundamental Science. Washington, D.C.: Optica Publishing Group, 2022. http://dx.doi.org/10.1364/cleo_qels.2022.fth4d.5.

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We demonstrate experimentally and numerically that many-body interactions between nanosized colloidal particles lead to subradiant regimes where the lifetime of emission long after the excitation ceases depends on the average particle-particle distance.
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Roth, Thomas, Philipp Rosenits, Marc Rudiger, Wilhelm Warta, and Stefan W. Glunz. "Comparison of photoconductance- and photo-luminescence-based lifetime measurement techniques." In 2008 Conference on Optoelectronic and Microelectronic Materials and Devices (COMMAD). IEEE, 2008. http://dx.doi.org/10.1109/commad.2008.4802138.

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Fu, Guoqing, and Sameer Sonkusale. "CMOS luminescence lifetime sensor for white LED multi-spectral characterization." In 2017 IEEE International Symposium on Circuits and Systems (ISCAS). IEEE, 2017. http://dx.doi.org/10.1109/iscas.2017.8051009.

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Labaki, H. P., F. J. Caixeta, N. P. Marques, E. J. Guidelli, L. C. V. Rodrigues, and R. R. Gonçalves. "Ultra-long lifetime, persistent luminescence, and scintillation features of Pr3+ and Na+ doped yttrium tantalates." In Latin America Optics and Photonics Conference. Washington, D.C.: Optica Publishing Group, 2022. http://dx.doi.org/10.1364/laop.2022.tu4a.23.

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In this work, we report the synthesis, structural, morphological, and spectroscopic characterization of Pr3+ and Na+-doped yttrium tantalates. An ultra-long lifetime, persistent luminescence and scintillation were observed making these materials potential candidates for nanomedicine applications.
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Romanishkin, I. D., V. Yu Proydakova, S. V. Kuznetsov, and D. V. Pominova. "Yb-Er-doped nanoparticles synthesis temperature effect on upconversion luminescence lifetime." In 2020 International Conference Laser Optics (ICLO). IEEE, 2020. http://dx.doi.org/10.1109/iclo48556.2020.9285676.

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Collier, Bradley, Ruiqi Long, and Mike McShane. "Dual-probe luminescence lifetime measurements for the oxygen compensation in enzymatic biosensors." In 2009 IEEE Sensors. IEEE, 2009. http://dx.doi.org/10.1109/icsens.2009.5398556.

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