Views:286 Author:Site Editor Publish Time: 2020-03-31 Origin:Site
Self-luminous materials are materials that can produce light emission under various types of excitation. It is mainly composed of matrix and activator. In addition, some cosolvent, co-activator and sensitizer are added in it.
The research of inorganic light storage materials has a long history, which can be traced back to 1866. In this year, the first inorganic light storage material with practical application significance was invented. At the beginning of the 20th century, Lenard studied the fluorescence decay curve and put forward the "central theory". However, due to the low luminosity and short life of this kind of self-luminous materials, people introduce radioactive materials into them. Although it can solve the above problems, it will harm human safety and the environment. Therefore, people turn their attention to other self-luminous materials. In 1934, when Haberlandt studied the natural CaF2 structure, it caused the ore to emit blue light. In 1964, the development and invention of self-luminous materials made the color TV rapidly popularized. In the 1980s, the research on the spectral characteristics of compound fluorides promoted the development of self-luminous products in China. Later, some new technologies for the preparation of self-luminous materials and a series of super persistence luminescent materials have been successfully studied, which has opened up a broad field for the application of self-luminous materials.
There are two kinds of self-luminous materials that people can see in life. Reflective materials can reflect the light on its surface quickly. The wavelength range of reflected light varies with different materials. The color of reflected light depends on what wavelength of light the self-luminous material absorbs and what wavelength of light it reflects, such as various license plates, traffic signs, etc. Fluorescent materials can absorb light of a certain wavelength and emit light of different wavelengths. When the incident light disappears, the fluorescent material immediately stops emitting light. More specifically, fluorescence refers to some quite bright color light seen by the human eye under the external light, such as green, orange and yellow.
There are two kinds of light radiation: balanced radiation and unbalanced radiation. As long as any object has a certain temperature, it must have radiation in thermal equilibrium with this temperature. Unbalanced radiation refers to the system that deviates from the original equilibrium state under the excitation of some external action. If an object returns to equilibrium, its excess energy will be released in the form of light radiation. Therefore, luminescence of the self-luminous material is a kind of non-equilibrium radiation superimposed on the background of thermal radiation, whose duration is longer than the vibration period of light.
The representative of inorganic self-luminous materials are rare earth ion luminescence and rare earth fluorescent materials. Its advantages include strong absorption capacity, high conversion rate, and stable physical and chemical properties. Due to the rich energy levels and electronic transition characteristics of rare earth ions, they provide excellent self-luminous materials for high-tech fields, especially in the field of information and communication. At present, the common inorganic light storage materials use alkaline earth metal sulfides and aluminates as the luminescent matrix. And they use rare earth lanthanide elements as activators.
In the field of luminescence, people pay more and more attention to the research of organic self-luminous materials. Because of the variety of organic compounds, good adjustability, rich color, high color purity and molecular design are relatively flexible. According to different molecular structures, organic self-luminous materials can be divided into organic small molecule self-luminous materials, organic polymer self-luminous materials and organic complex self-luminous materials. These luminescent materials have their own characteristics not only in luminescent mechanism but also in application.
Luminous powder is an ideal material for making luminous ink and luminous coating. Luminous ink is suitable for screen printing of all kinds of luminous effects, such as signs, toys, calligraphy and painting. Because of its high transparency, good film-forming and thin coating, it can be sprayed or printed on various self-luminous products.
The application of self-luminous materials in safety is the most common. In terms of safety, inorganic light storage materials can be used as exit indication marks, evacuation marks, etc. When they are used as these marks, inorganic light storage materials must be strictly tested to ensure that they meet the safety standards. The application of inorganic self-luminous materials is different from ornaments or other small articles in safety, which requires that the luminous materials maintain the brightest illumination and long-lasting illumination.