Rare earth luminescent materials in the LED industry

Solid white light-emitting diodes (LED lighting) will become a new generation of energy-saving light sources in the 21st century. One of the important ways to achieve white light emission is to use the fluorescence conversion technology of rare earth luminescent materials. Since 2014, China has announced a number of policies and measures in the rare earth industry to promote the rare earth industry to quickly get out of the bottom. With the WTO ruling that China’s rare earth case has lost, new rare earth control measures are being developed. The potential of rare earth luminescent materials in the LED industry is increasingly evident.

Luminescence properties of rare earth luminescent materials The rare earth luminescence is produced by the transition of rare earth 4f electrons between different energy levels. Due to the different excitation modes, the luminescence can be divided into photoluminescence, cathodoluminescence, electroluminescence, radioactive luminescence, and X-rays. Luminescence, triboluminescence, chemiluminescence, and bioluminescence. Rare earth luminescence has strong absorption ability, high conversion efficiency, and can emit spectrum from ultraviolet ray to infrared ray, especially in the visible light region OFweek semiconductor lighting network has a strong emission capability. Rare earth luminescent materials have been widely used in various aspects such as display images, new light sources, and X-ray screens.

Rare-earth light-emitting materials have narrow spectral bands, high color purity, and bright colors; strong light absorption capability, high conversion efficiency, wide emission wavelength distribution range, and fluorescence lifetimes from nanoseconds to milliseconds, up to 6 orders of magnitude; stable physical and chemical properties. , High temperature resistance, can withstand the role of high-power electron beam, high-energy radiation and strong ultraviolet light. It is these excellent properties that make rare earth compounds the main research object for the exploration of high-tech materials. With the continuous deepening of modern scientific research.

Researches on rare-earth luminescent materials have begun to tend towards nano-crystallization. Nano-crystallization of rare-earth luminescent materials undoubtedly gives some new characteristics of nano-particles based on the above original characteristics, such as quantum size effect, small size effect, surface effect and macroscopic Tunneling and so on. It can be seen that the nano-crystallization of rare earth luminescent materials will inject new vitality into this scientific research and will be more conducive to the discovery of new luminescent materials and new luminescent properties.

Application status of rare earth luminescent materials in the LED industry Because rare earth luminescent materials have the advantage that general luminescent materials cannot be replaced, it is widely used in electric light source lighting, television coloring materials, agricultural conversion materials, X-ray phosphors, Luminous paint and luminous ink, etc. Among them, electric light source lighting is the most important aspect of its application, and the output of fluorescent powder for lamps has taken the first place in all phosphors.

At present, the application ratio of incandescent bulbs, halogen powder fluorescent lamps and energy-saving lamps is currently about 4:3:1, and our country is about 8:9:1. Energy-saving lamps are the most mature environmental protection and energy-saving lighting products currently applied. They are the main application and promotion targets for implementing energy conservation and emission reduction in the current lighting field, accelerating the elimination of incandescent lamps, and achieving energy-saving lighting. At present, China is the world's largest producer of lighting products. In 2009, China produced 2.73 billion incandescent lamps and 3.5 billion fluorescent lamps. Among them, energy-saving lamps produced about 3 billion, accounting for more than 85% of the total output of fluorescent lamps. Therefore, in the face of a huge stock market and incremental market, the global elimination of incandescent lamps, the implementation of energy-saving lamp measures and the accelerated replacement of halogen-based fluorescent lamps will drive the rapid development of China's energy-saving lamp production industry.

The current output of rare earth luminescent materials has decreased, but the technology has greatly improved. In 2009, China's energy-saving fluorescent lamps (hereinafter referred to as "energy-saving lamps OFweek semiconductor lighting network") used rare earth luminescent materials sales of 6,160 tons, accounting for the total sales of rare earth luminescent materials industry 74.13% From 2010 to 2013, the use of rare earths in China's luminescent materials fell from 5,000 tons to 2,600 tons, and the proportion of total rare earth consumption fell from 5.78% to 3.1%. However, the technology of rare earth luminescent materials has been improved. In 2013, the market share of domestic LED powder exceeded that of imported powder, but there is still a certain gap with foreign technology. With the gradual implementation of the incandescent lamp project, LED will achieve explosive growth with a penetration rate of up to 20%. In 2013, the output of LED lamps exceeded 810 million.

The application prospects of rare earth luminescent materials in the LED industry The rare earth long afterglow luminescent material is a new type of environmentally friendly and energy-saving material. It can store some energy after absorbing sunlight and light energy, and then slowly stores the stored energy in visible light. Released in form, it can emit visible light for a long time after the light source is removed, and also has excellent characteristics such as high temperature resistance, friction resistance, high strength, scratch resistance, flame retardance, high chemical stability, etc. It is an ideal long-term energy saving and environmental protection. Optical materials have important value in fields such as construction, transportation and national defense.

In the field of photoconversion agricultural film, the luminescent material is used as a light conversion agent for sunlight, and added to agricultural plastic films to form agricultural films, which can improve the photosynthesis light quality, increase the utilization of light energy of crops, and thus can promote the early maturation of crops. And increase production.

In the field of lighting, solid white LEDs, which enjoy the reputation of the fourth generation of lighting sources, have attracted the attention of more and more researchers due to their outstanding advantages of energy saving, environmental protection and long life. LED will become a new generation of environmental protection and energy-saving light sources in the 21st century. It is precisely because of its irreplaceable advantages of other lighting sources, all countries in the world including China, the United States, Japan and Europe have increased their research in this area and are rushing to seize the intellectual property rights in this field.

In view of the outstanding performance of energy-saving lamps in terms of light efficiency, longevity, etc., in response to global climate change and energy shortages, in recent years, many countries or regions around the world have introduced plans to prohibit the use of incandescent lamps and promote the use of energy-saving lamps. From a global perspective, the trend of energy-saving lamps replacing incandescent lamps is irreversible.

Compared with halogen fluorescent lamps, energy-saving lamps (rare-earth fluorescent lamps) using rare earth luminescent materials have higher luminous efficacy, better color rendering, and longer service life. Energy-saving lamps can save 30% energy on the basis of halogen-based fluorescent lamps. -50%, color rendering index increased 15% -40%, life expectancy increased more than 3 times.

It is understood that the existing LED lighting sources use DC power as a driver, which must be converted by AC and DC power at work, which has large energy consumption, poor cooling, and high cost. Therefore, it is beneficial to develop new LED lighting products that can be directly driven by AC power. People, to promote the development of LED lighting industry, a major demand. In addition, at present, the series of products have passed the relevant certifications in China, as well as the United States Underwriters Laboratories (UL), the United States Federal Communications Commission (FCC), the European Union (CE) and the European Union Environmental Protection (RoHS) certification, sold to the United States, Canada, Mexico, Spain, Brazil and many other countries have achieved remarkable economic benefits.

In June 2013, the results of the “Research and Development of Luminescent Afterglow Controllable Rare-Earth LED Luminescent Materials and Their Applications in Semiconductor Lighting” jointly developed by the President of the Chinese Academy of Sciences (Caiyuan) Institute of Applied Chemistry and Chengdu Sichuan Xinli Light Source Co., Ltd. Through the identification of the results organized by the Chinese Academy of Sciences. The expert group believes that this original rare earth luminescent material effectively solves the problem of stroboscopic flashlight in exchange for LED lighting equipment that has not been able to break through internationally, and has achieved a leap from basic research to industrialization, reaching an international advanced level and making China a world leader. The only country that has mastered the production of low frequency flash AC LED products through rare earth phosphors.

The demand for rare-earth phosphors for energy-saving lamps continues to increase. There are two main reasons: First, the development of low-carbon economy in recent years has become a global hot spot. The use of energy-saving lamps can greatly reduce carbon emissions. Increased the productivity of LED energy-saving lamps; Second, because OFweek semiconductor lighting network in my country has strengthened the control of rare earth raw material exports in recent years, foreign manufacturers increase production costs, and gradually withdrew from the low-profit energy-saving lamp rare earth luminescent material market. In the next few years, with the implementation of incandescent lamp elimination policies in various countries and the increase in demand for downstream flat panel displays, rare earth luminescent materials will have a promising development prospect in the LED lighting application market, and their growth potential will continue to expand.

to sum up:

With the rise of energy-saving lighting, new technologies and new products of rare earth luminescent materials emerge in the LED industry. The industrial application of rare earth luminescent materials has seen explosive growth. Rare earth luminescent materials have become an indispensable basic material for energy-saving lighting and special light source production. With the continuous development of the application field, the rare earth luminescent material industry will exert great potential in the LED lighting industry in the future.