Preparation And Properties Of Long Lasting Materials With Mechanoluminescence Performance

Mechanoluminescence（ML） is a type of luminescence which is induced by mechanicalstimuli such as compression, tension, torsion or shock. Recently, the ML materials haveattracted more attention because of their potential applications for sensing structural damages,fractures and deformation. The rare earth doped luminescent materials have been investigatedin this paper. The results achieved in this paper are given as follows:（1） Phosphors with ultraviolet mechanoluminescence SrMgSi₂O₆:Ce、SrMgSi₂O₆:Ce,Erand Sr₂MgSi₂O₇:Ce,Er have been prepared by a solid state reaction method. The phosphorshave two emission bands at349and371nm under the excitation of325nm. The addition ofEr3+increases the ML intensity of SrMgSi₂O₆:Ce considerably. The formation of many trapsmay be responsible for this enhancement. At the same time, the structure of the phosphorsmay also influence the ML intensity.（2）①The Sr1-xMgSi₂O₆:Euxblue phosphors were synthesized by a solid state reaction.The phosphors emit bright blue luminescence with a peak wavelength at460nm, which isassigned to the4f65d�'4f7transitions of Eu²⁺. With increasing the amount of doping Eu²⁺upto1%, the luminescent brightness is the best. The ML intensity of phosphors enhancedremarkably following with increasing stress. At the same time, the ML intensity of phosphorsalso is nearly liner to the increase of pressure speeds.②The Sr0.99-xCaxMgSi₂O₆：Eu0.01（x=0-0.35） blue phosphors were synthesized by a solid state reaction. The XRD,photoluminescence emission spectra, the decay curve and the ML curve of phosphors wereinvestigated in detail. The phosphors emit bright blue luminescence which is assigned to the4f65d�'4f7transitions of Eu²⁺. Further studies on Sr0.99-xCaxMgSi₂O₆：Eu0.01indicated that theluminescence, the decay curve, ML intensity were influenced by Ca/Sr ratio. With increasingthe amount of doping Ca²⁺, the emission wavelength of Eu²⁺from470nm to443nm.Furthermore, the ML intensity of phosphors increased with increasing the amount of dopingCa²⁺. With Ca²⁺content of x=0.02, the Sr0.99-xCaxMgSi₂O₆：Eu0.01phosphor has the strongestML intensity.（3） The SrAl₂O₄：Eu，Dy green phosphors were synthesized by a solid state reaction. Theemission spectra of the sample show a green band located at514nm, which is due to the5d�'4f transition of Eu²⁺. We successfully prepared luminescence films with differentthicknesses. Furthermore, it can be observed that ML intensity increase following the increase in film thickness initially and reaches a maximum value at1mm, beyond which it decreasesslowly.