Autoluminescence

Autoluminescence is a phenomenon where a material emits light without any external energy input such as heating or electrical excitation. This spontaneous emission of light is a result of internal processes within the material. One common mechanism for autoluminescence involves the decay of excited electronic states within the material's crystal lattice or molecular structure. When atoms or molecules within the material transition from a higher energy state to a lower one, they can release the excess energy in the form of photons, which we perceive as light.

Another contributing factor can be the presence of naturally occurring radioactive isotopes within the material. The radioactive decay of these isotopes can release energetic particles that interact with the surrounding atoms, exciting them and leading to light emission. This process is often referred to as radioluminescence. Defects in the material's structure, such as vacancies or impurities, can also create localized energy levels that, upon relaxation, result in the emission of light. Autoluminescence is a fascinating area of study, with potential applications in areas like self-powered lighting and sensors. It is distinct from processes like fluorescence and phosphorescence, which require prior excitation by external energy sources.