(La, Gd) / BiOCl Phosphors And Their Luminescent Properties

With the development of the times and the progress of lighting technology, people are looking forward to researching the light emitting materials of high performance in order to achieve the purpose of energy saving and environmental protection. As a material with low phonon energy and good stability rare earth oxychlorides has attracted the attention of researchers. The crystal structure of rare earth oxychlorides belongs to the PbFCl type tetragonal structure, and the crystal structure from the theory is connected by van der Waals force of crystal plate layer, which is easy to form low dimensional two-dimensional layered crystal, and exhibited excellent luminescence properties of the matrix, and the physical and chemical nature. However, most of the rare earth oxychlorides show non orientation structure, which limits the further development and utilization of this kind of materials. To study the structure and the morphology of non oriented factors of rare earth oxychlorides, this paper takes LaOCl and GdOCl fluorescence powder prepared by the solid state method as the main object of study, which were compared with the tetragonal phase two-dimensional slice layer structure of BiOCl. Through the construction of oxychlorides solid solution by the evolution of La/Bi and Gd/Bi components, and the relationship between the fluorescence properties of solid solution matrix and rare earth ions Er3+ and Eu3+, the intrinsic reasons for the morphology and structure of rare earth oxychlorides matrix were studied.In La1-xBixOCl solid solution, with increasing Bi content, the crystal morphology gradually changed from small size of non orientation particles to the large size of the two-dimensional sheet structure change; broadband matrix fluorescence intensity located at 350 nm had a sharp decline in the trend. XPS and contrast experiments show that the matrix fluorescence originates were from the self-doping behavior of Cl in LaOCl. Through the self-doping behaviour and morphology, the group divided the evolution of the relation of Cl, we found that compared to the elements Bi, La element will cause the crystal structure in the adjacent Cl interlayer force increases, had an effect on the crystal growth process in the orientation behavior and two-dimensional slice layer structure formed. In addition, it is found that the self-doping behavior of Cl is helpful to improve the luminescence efficiency of rare earth ions.In Er3+ and Eu3+ doped Bi1-xLaxOCl solid solution, with the increase of La, induced the BiOCl special two-dimensional structure of Er3+ ion photon avalanche phenomenon disappeared quickly, the far red light emission behavior of Eu3+ gradually weakened. The fluorescence probe effect of rare earth ions (Er3+, Eu3+) was further confirmed by the effect of the chloride cation on the formation of two-dimensional structure.In Gd1-xBixOCl solid solution, the fluorescence properties of the substrate were opposite to that of LaOCl, which is mainly due to the vacancy defects of Cl. Crystal morphology evolution further confirmed that the Gd component of the Cl binding force is weakened, it is easier to form a layered structure. However, the fluorescence properties of rare earth ions with Gd group of change and Bi1-xLaxOCl solid solution were similar, further illustrates the tetragonal phase chlorine oxide cation group of nuances will significantly affect the two-dimensional layered structure in the physical and chemical properties.