Study on Rare Earth Luminescent Materials

The special electronic configuration of rare earth elements makes it a treasure house of new materials, and rare earth luminescent materials are colorful treasures in this treasure house. The luminescent properties of rare earth ions mainly depend on the properties of 4f shell electrons of rare earth ions. The general electronic configuration of rare earth ions is (Xe) (4f) n (5s) 2 (5p). With the change of 4f shell electron number, rare earth ions show different electronic transition forms and extremely rich energy level transitions. The research shows that there are 1639 energy levels in 4f electron configuration of rare earth ions, and the number of possible transitions between energy levels is as high as 199177, and more than 30000 lines can be observed. If 4f ~ 5d energy level transitions are involved, the number will be even more, so rare earth ions can absorb or emit light of various wavelengths from ultraviolet to infrared to form various luminescent materials. The excellent luminescent properties of rare earth ions lay a foundation for making efficient luminescent materials with them.
Rare earth luminescent materials once played a milestone role in the development of luminescent optics and luminescent materials. In 1908, Becguerel discovered rare earth sharp absorption lines. In 1959, the phenomenon of photon addition with Yb* as sensitizer and E*, Ho* and Tm* as activators was discovered, which laid the foundation for the research and development of upconversion materials. The appearance of red powder in YVO: Eu ,Y03:Eu in 1964 and 0,S:Eu in 1968 raised the brightness of color TV to a new level. The infrared visible upconversion materials appeared in 1970s, which put forward the anti-Stokes effect in theory. In 1973, rare earth tricolor phosphors (BaMgAloO: Eu, MgAl,O,: Ce, Tb, Y,0,:Eu) were discovered, which improved the quality of electric light source to a new level. In 1974, photon clipping was found in the compound of P* ions, that is, absorbing a high-energy photon and splitting it into two or more photons with lower energy; Rare earth long afterglow phosphors (SrAl,0,: Eu, SrAl,0: Eu, RE) appeared in 1990s.
At the end of 1950s, with the breakthrough of rare earth separation technology in China, high-purity single rare earth oxide was prepared, which provided material conditions for the development of rare earth luminescent materials. China began to develop rare earth luminescent materials in the middle and late 1960s. In recent 30 years, rare earth luminescent materials have been widely used in many fields in China. In 1970s, Y(P, V)0:E red powder for high-pressure mercury lamps was developed. Y,0, ∶Eu and Y,0,S∶Eu red powder for color TV; Lights were developed in the 1980s.
Rare earth tricolor phosphor, X-ray intensifying screen, infrared visible upconversion material, etc. A variety of phosphors such as rare earth phosphors and rare earth long afterglow materials for plasma display (PDP) were developed in the O’s: at the beginning of the 21st century, phosphor for Baiyao LET was developed vigorously. At present, the rare earth luminescent material industry in China has occupied a place in the world.
There are many kinds of rare earth luminescent materials and their applications are wide, and there are more than .300 kinds of known rare earth luminescent materials. At present, rare earth luminescent materials are mainly used in energy-saving lamps, semiconductor lighting, flat panel display, scintillation crystals and other fields. They have become one of the supporting materials in energy-saving lighting, information display, photoelectric detection and other fields, and have played an important role in technological progress and social development (‘2]. The development trend of luminescent materials shows that rare earth luminescent materials have gradually replaced non-rare earth luminescent materials, which has become the dominant research and application of luminescent materials, and is the focus and frontier of luminescent materials research. Therefore, the competition at home and abroad is very fierce.
Rare earth luminescent materials have not only become one of the main fields of rare earth application in China, but also one of the most important ways to realize the high value of rare earth resources. China is rich in rare earth resources, which has laid a foundation for the development of rare earth luminescent industry in China.