Rare earth materials | rare earth luminescent material

Rare earth elements play a big role in these luminescent materials

Since ancient times, humans have preferred light and feared darkness, dreaming of controlling light at will, and now we have developed many practical luminous materials.  In these luminescent materials, rare earth elements play a big role, far more than other elements.  Due to the unique electron layer structure of rare earth elements, rare earth compounds show many excellent optical, electric and magnetic functions, especially rare earth elements have incomparable spectral properties, so the application of rare earth luminescent materials is particularly attractive.  

Since 1964, Y2O3: Eu3+ has been used to manufacture phosphors, as long as it comes to light, it is inseparable from rare earth.  Rare earth luminescence covers almost the whole category of solid state luminescence, and has become the supporting materials in display, lighting, photoelectric devices and other fields, and new rare earth phosphors are constantly appearing.  

The unique electronic structure of rare earth elements determines its special luminescent properties

Rare earth compounds are widely used in luminescent materials because of their advantages as follows:  

1. Compared with ordinary elements, rare earth elements have various fluorescence characteristics due to their 4F electron layer configuration.  Except Sc3+ and Y3+ have no 4F sublayer, and La3+ and Lu3+ have empty or full 4F sublayer, 4F electrons of other rare earth elements can be randomly distributed among 7 4F orbitals, thus generating abundant electron energy levels, which can absorb or emit electromagnetic radiation of various wavelengths from ultraviolet, visible light to near-infrared region.  The rare earth luminescent materials present rich and varied fluorescence characteristics.  

2. Rare earth elements are difficult to be interfered by the external environment because 4F electrons are in the inner orbit and are effectively shielded by the outer S and P orbits. The 4F energy level difference is very small, f-F transition presents a sharp linear spectrum, and the color purity of luminescence is high.  

3. Fluorescence lifetime spans 6 orders of magnitude from nanosecond to millisecond.  Long-life excited states are one of its important characteristics. The average lifetime of the excited states of ordinary atoms or ions is 10-10 ~ 10-8s, while the average lifetime of some excited states in the electron energy levels of rare earth elements is 10-6 ~ 10-2s, which is mainly caused by the low probability of spontaneous transition between 4F electron energy levels.  

4. Strong ability to absorb excitation energy and high conversion efficiency.  

5. Stable physical and chemical properties, can withstand the effect of high power electron beam high-energy radiation and strong ultraviolet.  

Rare earth luminescent materials have created a colorful world for human beings. Meanwhile, due to the high added value of their products, they have also brought great economic benefits to producers.  Since the high purification of rare earth oxides was realized in the 1960s, major technological breakthroughs have been made in the field of rare earth luminescence. The development, production and application of color TV phosphors, mobile phone screen phosphors, three-color lamp phosphors and medical image phosphors have made rapid progress.  

According to statistics, the total consumption of rare earth in rare earth luminescent materials is less than 4% of the total consumption of rare earth, but its output value accounts for 41% of the total sales of rare earth application market, making it the hottest industry in the rare earth industry.