Phosphor

A phosphor, most generally, is a substance that exhibits the phenomenon of luminescence. Somewhat confusingly, this includes both phosphorescent materials, which show a slow decay in brightness (> 1 ms), andfluorescent materials, where the emission decay takes place over tens of nanoseconds. Phosphorescent materials are known for their use in radar screens and glow-in-the-dark materials, whereas fluorescent materials are common in cathode ray tube (CRT) and plasma video display screens, sensors, and white LEDs.

Phosphors are often transition metal compounds or rare earth compounds of various types. The most common uses of phosphors are in CRT displays and fluorescent lights. CRT phosphors were standardized beginning around World War II and designated by the letter "P" followed by a number.

Phosphorus, the chemical element named for its light-emitting behavior, emits light due to chemiluminescence, not phosphorescence;^[1]

Contents

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• 1Principles
  • 1.1Phosphor degradation
• 2Materials
• 3Applications
  • 3.1Lighting
  • 3.2Phosphor thermometry
  • 3.3Glow-in-the-dark toys
  • 3.4Radioluminescence
  • 3.5Electroluminescence
  • 3.6White LEDs
  • 3.7Cathode ray tubes
• 4Standard phosphor types
  • 4.1Various
• 5See also
• 6References
• 7Bibliography
• 8External links