The Study Of La₂Zr₂O₇:Sm³⁺ Prepared By Polymer Network Gel Method And Ions Co-doped Modification

Rare earth fluorescent materials have been widely used in fluorescent lamp materials,fluorescent displays,solar energy materials,light absorption enhancement,photocatalytic energy conversion,biological imaging,targeted diagnosis and treatment and other fields.Among the preparation methods of rare earth fluorescent materials,the reaction temperature of solid phase synthesis method is too high,and the mixing of raw materials is not uniform.Other wet chemical methods are limited by the cost and reaction conditions,which is not conducive to large-scale promotion.Polymer network gel method is an ideal method for preparing inorganic materials because of its advantages such as uniform mixing of raw materials,simple process,low pollution and low cost.In this paper,La₂Zr₂O₇:Sm³⁺fluorescent powder was synthesized by polymeric network gel method,and its luminescence properties and the modification of co-doped ions were studied.（1）The powders are pyrochlorite structures with good luminescence properties.Under the excitation of 407nm excitation light,the 565 nm emission peak representing⁴G_5/2→⁶H_5/2 transition process is obtained,the 606 nm emission peak representing⁴G_5/2→⁶H_7/2 transition process is obtained,and the 652 nm emission peak representing⁴G_5/2→⁶H_7/2 transition process is obtained.The results show that the characteristic emission intensity increases first and then decreases with the increase of the doping concentration of samarium ion at different sintering temperatures.When the doping concentration reaches 2.5 mol%or 5.0 mol%,the maximum emission intensity of the powders at different sintering temperatures is achieved.The particle size of the powder increases with the increase of sintering temperature,and the emission intensity increases first and then decreases with the increase of sintering temperature.After sintering at 850℃for 2 h,the emission intensity reaches a large level.（2）The effect of the co-doping of alkali metal elements and trivalent ions on the luminescence properties of the powders was investigated.On the one hand,the addition of alkali metal elements intensifies the lattice distortion,promotes the formation of lattice and the improvement of crystallinity,which is conducive to the enhancement of emission performance.On the other hand,due to the existence of internal defects in the matrix material,the lattice vibration is enhanced by the distortion,which weakens the emission intensity of Sm³⁺.The doping of Eu³⁺and B³⁺trivalent ions produces lattice distortion and less vacancy defects.When sintered ar 950℃,the microsymmetry is adjusted to facilitate the forbidden transition of activated ions and improve the emission performance of powders.