What are the types of luminescence?

The types of luminescence include: fluorescence, bioluminescence, chemiluminescence, phosphorescence, crystalloluminescence, photoluminescence, electroluminescence, mechanoluminescence,radioluminescence, and thermoluminescence.

Chemiluminescence

Chemiluminescence is the emission of light as a consequence of a chemical reaction. This luminesce can be observed by bending and shaking a light stick that contains an encapsulated chemical solution surrounded by a different chemical solution. Bending the stick causes the encapsulated chemical solution to break open and then the two solutions are then mixed by shaking the stick. As a result, light is created. Bioluminescence (which is a form of chemiluminescence) is defined as the production and emission of light by a living organism. Bioluminescence primarily occurs in marine vertebrates and invertebrates, as well as some fungi. An example of a marine invertebrate that uses bioluminescence is the jellyfish aequorea victoria. Luciferin, which a jellyfish produces on its own or gets it through its diet, reacts with oxygen to release and produce light; it is luciferin that is physically producing the light. The enzyme luciferase catalyzes this reaction. When they react, luciferase catalyzes the oxidation of luciferin to create an unstable excited molecule. As it decays (to ground state), the light is produced, and the product oxyluciferin is also produced. It is important to note that for every reaction, light is only produced once. In order for it to occur again, the organism must bring in more luciferin into its system.  Jellyfish use bioluminescence to defend themselves from predators, while other creatures like male sea-fireflies use bioluminescence to attract mates.

Phosphorescence

Phosphorescence is the ability of a material to absorb energy from an electromagnetic radiation source, (e.g. flashlight) and then continue to emit light after the source is removed. A glow in the dark objects absorbs or stores energy from the flashlight and then re-emits energy as light after the flashlight is turned off.

Fluorescence

Fluorescence is the ability of a material to emit light through absorbing energy from electromagnetic radiation. These materials can only emit light in the time that they are exposed to the source of electromagnetic radiation. A fluorescent substance will stop emitting light once the light source is removed, unlike phosphorescence.  

Crystalloluminescence

Crystalloluminescence is the effect of light produced during crystallization. It has been suggested that light comes from small cracks in the crystal. For example, the crystallization of potassium iodide and KCL exhibits luminescence in the regions of 380-480 and 240-380 millimicrons respectively. Electroluminescence is when a substance produces light as a consequence of the passage of an electric current or an electric field. An example is cathodoluminescence, which occurs after electrons collide with a luminescent material. Electroluminescence is unique because  a direct conversion of electric energy into visible light occurs with the production of heat (e.g. incandescent lamps). The two types of electroluminescence are intrinsic and charge injection. During intrinsic electroluminescence, thermal activation and electric fields free atomic electrons into the conduction band. These electrons are accelerated by the electric field until they collide with luminescent atoms, ionizing them. When an electron collides with a luminescent substance (ionized atom), light is emitted.During charge injection, an electrode comes into contact with a crystal to give off a flow of electrons. A voltage may also be applied to a p-n junction, also causing current flow (electrons flow to the p- and n- type material. 

Chemiluminescence

Chemiluminescence is the emission of photons when excited molecules decay to their ground state (proceeding a chemical reaction). The luminol reaction is an example of chemiluminescence. During the reaction, luminol reacts with hydrogen peroxide to release blue light. The quantity of light released by the reaction is small unless a small amount of appropriate catalyst is added (usually a small quantity of copper or iron).  

Radioluminescence

In radioluminescence, is the generation of optical photons from the interaction of ionizing radiation with matter. An example is tritium- excited luminous paints that are used on watch dials. Thermoluminescence is the emission of light from certain minerals and certain other crystalline materials. An example is when the minerals quartz or calcite, which previously absorbed energy, become re-emitted as light upon heating.

Photoluminescenc

Photoluminescence is the process in which a molecule absorbs a photon in the visible religion, exciting one its electrons to an excited state. It then radiates a photon as the electron returns to its ground state. An example is fluorescence, which emits photons as electrons are excited from their ground state in a rapid manner (nanoseconds). Another example is phosphorescence, which emits protons that have been “trapped”, in a delayed manner (milliseconds to hours).