Luminescerende

Luminescerende describes any material or process that emits light without being primarily heated, i.e., not incandescence. The light is produced by electronic transitions, chemical reactions, or specialized materials. Luminescence is typically categorized by mechanism, such as fluorescence, phosphorescence, chemiluminescence, bioluminescence, electroluminescence and triboluminescence.

In fluorescence, a material absorbs energy and emits light almost instantaneously, vanishing within nanoseconds after excitation ends. Phosphorescence involves longer-lived emission because the excited state decays via forbidden transitions, causing an afterglow that can last microseconds to hours. Chemiluminescence is light produced by a chemical reaction, as in glow sticks; bioluminescence is chemiluminescence produced in living organisms, such as fireflies, via enzymes like luciferase and substrates like luciferin. Electroluminescence arises when electrical energy drives light emission, a principle behind LEDs and OLEDs. Triboluminescence produces light when materials are fractured, rubbed, or milled.

Materials that exhibit luminescence include organic fluorophores, inorganic phosphors, and rare-earth–doped crystals. Phosphors used in LEDs and displays convert electrical energy into visible light; luminescent polymers and dyes enable imaging and sensing. Emission spectra (color) and lifetime are key properties, as are quantum yield and stability under light exposure.

Applications of luminescent materials span safety signage, decorative lighting, displays, medical imaging, forensic analysis, and art. Historically, luminescent materials included radium-based paints, later replaced due to radiation hazards. Today’s luminescent technologies emphasize efficiency, longevity, and environmental safety.