Learn Fluorescence definition and factors affecting fluorescence, a condition when a substance absorbs light and emits a longer wavelength.
What is Fluorescence?
Fluorescence is a phenomenon in which a substance absorbs light at a specific wavelength and then emits light at a longer wavelength. This emission of light occurs when the absorbed energy causes an electron in the molecule to move to a higher energy level and then fall back to its original energy level, releasing energy in the form of light. The emitted light has a longer wavelength than the absorbed light and is typically in the visible or ultraviolet range. Fluorescence has many applications, including biological imaging, environmental monitoring, and materials science.
What is Fluorescent?
“Fluorescent” is an adjective used to describe something that exhibits fluorescence, which is the phenomenon where a substance absorbs light at a specific wavelength and then emits light at a longer wavelength. For example, a fluorescent dye is a substance that can absorb light at a specific wavelength and emit light at a longer wavelength, making it useful for fluorescence-based applications such as biological imaging or chemical analysis.
Factors affecting fluorescence
Several factors can affect fluorescence, including:
- Excitation wavelength: The wavelength of the excitation light can affect the intensity and spectral characteristics of fluorescence.
- Quantum yield: This is a measure of how efficiently a molecule can convert absorbed light into fluorescence. Factors that affect quantum yield include molecular structure, solvent polarity, and temperature.
- Environmental factors: The local environment of a fluorescent molecule can have a significant impact. For example, pH, temperature, and the presence of quenching agents or other fluorescent molecules can affect intensity and spectral properties.
- Concentration: The concentration of a fluorescent molecule can affect its intensity, with higher concentrations often resulting in greater fluorescence.
- Chemical structure: The chemical structure of a fluorescent molecule can affect its properties, such as the wavelength of maximum emission and the shape of the emission spectrum.
Applications
- Biological imaging: Fluorescent molecules can be used to label specific biological molecules, cells, or tissues for imaging purposes, allowing researchers to visualize and study biological processes in real-time.
- Clinical diagnostics: Fluorescence-based assays can be used for the detection and quantification of various biomolecules, such as DNA, proteins, and enzymes, in clinical samples.
- Environmental monitoring: To detect and quantify environmental pollutants, such as heavy metals, pesticides, and organic compounds, in water and soil samples.
- Materials science: To study the properties and behavior of materials, such as polymers, nanoparticles, and quantum dots.
- Forensic science: To detect and identify trace amounts of substances, such as blood or fingerprints, at crime scenes.
- Chemical analysis: To quantify various chemical species, such as ions, acids, and bases, in chemical samples.
- Quality control: To monitor the quality and purity of various products, such as pharmaceuticals, food, and beverages.
Also read What is Fluorimetry? theory and application. Spectral shifts in UV-Visible Spectroscopy