The difference between phosphorescence and fluorescence

The difference between phosphorescence and fluorescence is that when the incident light of phosphorescence stops, the luminescence phenomenon will continue to exist. And many fluorescent substances once the incident light stops, the luminous phenomenon also disappears immediately.

One, phosphorescence is a slow luminescence photocooling luminescence phenomenon. When some kind of room temperature material by a certain wavelength of incident light (usually ultraviolet or X-ray) irradiation, absorption of light energy into the excited state (usually has and the base state of different spin multiplicity), and then slowly back to the excitation and emit than the wavelength of the incident light wavelength of the light (usually wavelengths in the visible wavelength band).

When the incident light stops, the luminescence persists. The de-excitation process of emitting phosphorescence is forbidden by the leapfrog selection rules of quantum mechanics, so the process is slow. So-called "glow in the dark" materials are usually phosphorescent, such as pearl of the night.

Two, fluorescence, also known as "fluorescence", refers to a photoluminescence cold luminescence phenomenon. When some kind of room temperature material by a certain wavelength of incident light (usually ultraviolet or X-ray) irradiation, absorption of light energy into the excited state, and immediately back to the excitation and emit a longer wavelength than the incident light emitted light (usually wavelengths in the visible wavelength band).

Many fluorescent substances, once the incident light stops, the light-emitting phenomenon also disappears immediately. Outgoing light with this property is called fluorescence. In addition, there are some substances in the incident light is withdrawn can still glow for a long time, this phenomenon is called afterglow. In daily life, people usually broadly to a variety of weak light are called fluorescence, but not to carefully investigate and distinguish its luminous principle.

Extended information:

Phosphor materials (phosphor materials), materials that emit phosphorescence when excited by electromagnetic radiation and ionic rays.

Long afterglow luminescent materials are typically phosphorescent. According to the form of single crystal, thin film, microcrystalline powder and microcrystalline glass. Commonly available sulfides, oxides, II-IV and IV-V compounds, rare earth luminescent materials. Typical materials are zinc sulfide ZnS: Cu, ZnS: MnCu, ZnS: Cu, Eu, Br, etc.; alkaline earth sulfide CaS: Eu, CaS: Ce, oxide MgAI11O9: Ce, Tb, etc..

Performance can be characterized by luminescence spectrum, efficiency, lifetime, intensity, color coordinates. Spectral peak, color can be adjusted by adding activators, *** activators, sensitizers such as Cu, Al, Re, etc. The spectral peak can be within 480 to 550nm, and colors such as green, blue, orange, orange-red, etc. can be obtained. It can be used in display panels, fluorescent lamps, ionizing radiation detection, aircraft instrument panels, laser and infrared night-vision devices, etc. It has a wide range of applications as a display material.

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