Research progress on spectral characteristics of luminous fiber

The spectral shift of rare earth luminous fiber comes from the spectral change of rare earth ions in the fiber, because of the night the spectral characteristics of optical fiber and rare earth luminescent materials used in spinning are very similar, but there are differences in relative intensity and wavelength range. Therefore, it is very important to study the spectral status of rare earth ions. It has been more than a century since people discovered the spectrum of rare earth ions. Becquerel accidentally discovered that there was a particularly sharp spectral line in an ore containing rare earth and transition elements in 1906. Later, it was found that this spectral line was similar to the absorption and emission spectral lines of gas chemical elements, but it did not attract the full attention of researchers at that time, thus affecting the study of the spectral characteristics of rare earth elements to some extent. After Bohr's atomic theory in 1913, quantum mechanics in 1926, Bethe's crystal field theory in 1929 and Condon-Shortley's atomic spectrum theory appeared, the spectral phenomenon of rare earth elements gradually attracted scientists' research interest. Subsequently, researchers at home and abroad began to study spectroscopy, further confirming that the forbidden transition in 4f shell of rare earth ions determines the absorption spectrum of the above-mentioned sharp-line rare earth ions. After 1950s, the spectroscopy of rare earth ions and its theory began to develop in the United States, Britain, France, the Netherlands and Switzerland, and a special rare earth spectroscopy laboratory was set up at Hopkins University in the United States. Since then, books on spectroscopy have been published in the world, which concentrated on the spectral energy levels of rare earth ions and the spectral behavior of 4f "configuration. However, the research on rare earth luminescent materials in China began in 1970s, and some scientific research institutions and universities began to study rare earth luminescent materials and their spectral characteristics, and made some achievements in theoretical research on display materials, rare earth luminescence and luminescence basis.

In recent years, with the development of science and technology and the emergence of new scientific phenomena, the study of refined spectral behavior such as multiphoton absorption process, high excited energy level spectrum and nonlinear spectral phenomena has developed rapidly. However, these spectral behaviors are mainly concentrated in the field of physics, and the research on the application of rare earth ions in the field of textiles, especially in the field of functional fibers, is very rare, and there are only a few related studies. As shown in Figure 1-3, the yellow-green luminous fiber doped with Sralo.: EU+and DY+ is jointly developed by Jiangnan University and Wuxi Hongyuan Chemical Fiber Factory, which fills the gap in the application of rare earth elements in the textile field in China and belongs to the first high-tech functional fiber in China. In addition, the physical properties, luminescent properties and spectral behavior related to the fiber are systematically studied by the differential laboratory of the School of Textile Science and Engineering of Jiangnan University. The compatibility between organic compounds and polymer substrates is good, and it is easy to prepare various polymer luminescent materials. "Domestic scholars have conducted related research on the spectral characteristics of this kind of luminescent materials. For example, in 2014, Zhu Yanan [] studied the spectral characteristics of the composite noctilucent fiber of oxaanthracene derivative/rare earth strontium aluminate, and considered that the addition of oxaanthracene derivative made the spectrum of noctilucent fiber red-shifted, and discussed the influencing factors of the spectrum red-shifted.

Rare earth luminous fiber spectrum is widely used, and its unique emission spectrum is as different as human fingerprints. Each element has its own spectral line, and the spectral characteristics of doped rare earth luminescent materials are the main reason for the yellow-green light produced by luminous fibers. Using the spectral characteristics of rare earth luminous fiber can not only qualitatively analyze the structure and chemical composition of the substance, but also identify the light color of the starting substance, and even accurately determine the number of elements in the luminescent material. The analysis speed is fast, which greatly improves the efficiency of scientific research.