Lumineszente

Lumineszente refers to the emission of light by a substance not produced by heat. In luminescence, excited energy is released as photons when the material returns to lower energy states after stimulation by chemical reactions, electrical energy, or other energy sources. The process can be rapid or persistent and may occur under various environmental conditions.

Different forms are categorized by the source of excitation. Photoluminescence includes fluorescence and phosphorescence, where light is emitted after optical excitation. Chemiluminescence arises from chemical reactions, while bioluminescence is produced by living organisms. Electrochemiluminescence involves electrical energy, and triboluminescence occurs from mechanical action. Persistent luminescence stores energy in trap states within a material and releases it over extended times after the initial excitation.

Materials that exhibit luminescence include phosphors, quantum dots, organic dyes, and bioluminescent proteins. Persistent phosphors such as strontium aluminate doped with europium and dysprosium are used in glow-in-the-dark products. Natural luminescence is observed in fluorescent minerals and in some types of glass, such as uranium-containing glass. Practical examples include glow sticks, which rely on chemiluminescence to produce light without an external power source.

Applications of luminescence span several fields. They are central to lighting technologies and display devices (such as LEDs and OLEDs), as well as to bioimaging and biosensing through fluorescent probes. Security features, calibration standards, and anti-counterfeiting measures also rely on luminescent materials. The study of luminescence informs materials science, chemistry, and biology, supporting advances in diagnostics, lighting efficiency, and sensing technologies.