Preparation and characterization of new red luminescent fibers based on a multilayer structure

Composite red luminescent material SMED/LCA (Sr 2 MgSi 2 O 7 :Eu 2+ ,Dy 3+ /light conversion agent) is a phosphor with long afterglow, which was prepared by LCA and SMED at a certain mass ratio. It has excellent characteristics, such as high lightness and emitting red light, but poor stability properties because LCA falls off easily from the surface of SMED. Here, SiO 2 (Al 2 O 3 or MgF 2 ) was coated on the surface of SMED/LCA through the heterogeneous deposition method to prepare a stable composite phosphor, adding coated phosphor into a polyacrylonitrile (PAN) fiber-forming polymer and wet spinning to form SMED/LCA-PAN (composite red light-emitting fiber). The surface element distribution, phase structure and luminescence properties of SMED/LCA-PAN were characterized. The results show that SiO 2 (Al 2 O 3 or MgF 2 ) is successfully coated on the surface of the material, and the coating has no effect on the phase of SMED in the fibers. The intensity red/blue ratio (Int.600 nm versus Int.470 nm) of coated SMED/LCA fiber in the afterglow emission spectrum increases by about 1.9 times; the increase in energy conversion efficiency indicates the enhancement of the red light effect. In addition, the afterglow initial brightness is up to 0.148 cd/m 2 after 15 min of ultraviolet light excitation, and the luminous fiber still has high afterglow brightness.