Phosphorescence Detection
Phosphorescence Detection - Related Videos
10:38
Synthesis and Calibration of Phosphorescent Nanoprobes for Oxygen Imaging in Biological Systems
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Cited by 2 •
2010
We present principles of oxygen measurements by phosphorescence quenching and review design of porphyrin-based dendritic nanosensors for oxygen imaging in biological systems.
08:58
Cerebral Blood Oxygenation Measurement Based on Oxygen-dependent Quenching of Phosphorescence
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Cited by 28 •
2011
We present an experimental procedure for measuring the partial pressure of oxygen (pO2) in cerebral vasculature based on oxygen-dependent quenching of phosphorescence. Animal preparation and imaging procedures were outlined for both large field of view CCD-based imaging of pO2 in rats and 2-photon excitation based imaging of pO2 in mice.
01:23
Photoluminescence: Fluorescence and Phosphorescence
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2024
Photoluminescence is a process where a molecule absorbs light energy and re-emits it in the form of light. This phenomenon occurs when a substance absorbs photons, promoting its electrons to higher energy level excited states, followed by a relaxation process in which the electrons return to their original ground state energy levels and emit light. Photoluminescence is widely observed in various materials, including semiconductors, and organic and inorganic compounds. A pair of electrons in a...
01:26
Variables Affecting Phosphorescence and Fluorescence
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2024
Fluorescence and phosphorescence are essential phenomena in fields like analytical chemistry, biological imaging, and materials science, where they detect molecular properties and visualize cellular structures. Understanding the variables that influence these luminescent behaviors is crucial for maximizing accuracy and efficiency in their applications. These variables can broadly be grouped into chemical structure, solvent properties, and external conditions, each playing a distinct role in...
01:25
Fluorescence and Phosphorescence: Instrumentation
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2024
Fluorometers and spectrofluorometers are two types of instruments used for measuring molecular fluorescence. These instruments differ in how they select excitation and emission wavelengths and the type of light sources they utilize. Fluorometers use absorption interference filters to choose excitation and emission wavelengths. The excitation source in a fluorometer is typically a low-pressure mercury vapor lamp that emits intense lines distributed throughout the ultraviolet and visible regions.
FAQs
The triplet state persists longer than the initially excited state, so emission can continue after the excitation source is reduced or removed. This separation allows the detector to distinguish the delayed signal from prompt light produced during excitation. Measuring that time-dependent response gives access to molecular behavior that is not described by emission intensity alone.
Intersystem crossing transfers an excited molecule into a triplet state before it returns to the ground state. That change in electronic state creates the longer-lived pathway responsible for delayed emission. Its occurrence is therefore central to detecting phosphorescence and to interpreting how molecular structure or chemical surroundings influence the observed signal.
Emission intensity indicates how much phosphorescent light is recorded, whereas lifetime describes how long the excited-state emission persists. Considering both measurements helps characterize molecular behavior more fully than either value alone. Changes in these parameters can reflect differences in chemical environment, molecular interactions, or the presence of species that affect the excited state.
A sample is first exposed to an excitation source so its molecules absorb energy and reach excited states. The measurement then follows emission after the source is reduced or removed, recording the delayed photons and, when needed, their persistence over time. The resulting intensity or lifetime can then be related to chemical environment and molecular behavior.
Oxygen and other quenchers can alter the phosphorescent response by affecting excited-state behavior. Monitoring changes in emission intensity or lifetime provides a way to investigate those interactions. In chemistry, this approach supports sensing and helps assess how the surrounding chemical environment influences a phosphorescent molecule or material.
Transition-metal complexes are important because their phosphorescence can be characterized through emission intensity and lifetime. Time-resolved measurements help examine their molecular behavior and chemical environment, while also supporting quantitative analysis. The same measurements can contribute to studies of photochemistry, where delayed emission provides information about excited-state processes.