Rare earth phosphors are phosphors made of rare earth ions activated in an appropriate matrix. Rare earth phosphors usually emit visible light but can also emit up to ultraviolet (UV) light. The rare earths used in phosphors are lanthanides and include elements such as Cerium, Gadolinium, Ytterbium, Europium, and Terbium.
The broad definition of rare earth phosphors includes many types of phosphors. These can be divided into several categories, including cathodoluminescent or “CL” phosphors, fluorescent phosphors and color-converting phosphors. CL phosphors emit a range of low-energy photons when energized by an external electron beam, such as electrons from a cathode ray tube. These photons can be detected and recorded, and the CL phosphors are commonly used in imaging devices such as CRT televisions and medical imaging devices.
Fluorescent phosphors are activated by a UV light source and this energy is converted into visible light. These phosphors are commonly used in compact fluorescent lamps and other lighting systems. Color-converting phosphors are excited by UV light and emit different colors of visible light, depending on the chemical structure of the phosphor. These phosphors are used in color converting lamps and light fixtures, as well as for special color effects in display systems.
Rare earth phosphors are also used in a number of other applications. They are used as scintillators in medical and laboratory equipment. Scintillators detect and measure radiation, such as gamma rays and X-rays. The radiation interacts with the scintillator material, resulting in a visible emission that can be detected. They are also used in optical devices such as lasers and digital displays.
The use of rare earth phosphors is increasing as they possess a range of advantages. They are more efficient than other types of phosphors and emit brighter, more intense light. They are also more durable than other phosphors, making them suitable for long-term use. Finally, rare earth phosphors can be tailored to emit different colors of light making them ideal for applications such as lighting and displays.
Although rare earth phosphors offer many advantages, there are also some drawbacks. They are generally more expensive than other types of phosphors and can be difficult to manufacture. They can also be toxic if not handled properly, making them unsuitable for some applications.
In summary, rare earth phosphors are an increasingly popular type of phosphor. They emit brighter, higher energy light than other types of phosphors, making them suitable for a wide range of applications. They are more expensive and potentially more toxic than other phosphors, but their increased performance and durability may outweigh the disadvantages for many applications.
