应力发光材料Sr2SiO4∶Eu,Dy的光谱性质研究

Spectrum Properties of Mechanoluminescent Materials Sr_2SiO_4∶Eu,Dy

采用高温固相法制备一系列Sr_2SiO_4∶Eu0.01,Dy_x(x=0.000 1,0.002 5,0.005,0.01)应力发光材料,研究了不同掺杂浓度下,Sr_2SiO_4∶Eu,Dy的光致发光和应力发光性质。研究结果表明在掺杂Dy^(3+)浓度较低时,样品同时存在α和β两种相,当掺杂Dy^(3+)浓度增加时,则出现β到α的相转变。由于Eu^(2+)占据Sr^(2+)格位的不同,样品在蓝光区486nm(Sr1)和绿光区530nm(Sr2)有两个峰存在。而应力发光光谱与余辉光谱类似,均只呈现出530nm的发光,这说明二者的发光来源于占据Sr_2格位的Eu^(2+),都是通过改变陷阱的浓度实现发光性能的变化,但Sr_2SiO_4∶Eu,Dy的应力发光强度的变化还与其结构改变有关。同时,Sr_2SiO_4∶Eu,Dy应力发光强度与所施加的力之间呈良好的线性关系,并且可用眼睛观察到明显的黄色应力发光,这为应力发光传感器准确检测物体所受应力提供依据。结合余辉、热释以及应力发光性质,推测Sr_2SiO_4∶Eu,Dy的应力发光机制应是压电产生的电致发光。

The mechanoluminescence（ML）materials Sr2SiO4∶Eu,Dy were prepared by high temperature solid-state reaction method.The luminescent and mechanoluminescent properties of Sr2SiO4∶Eu,Dy with different Dy^3＋concentrations have been investigated.The results showed thatαandβphases of Sr2SiO4 co-existed for the low doped content of Dy^3＋.When the doped Dy^3＋concentration increased,theβphase transited intoαphase gradually.Since the Eu^2＋ions occupied different Sr sites,the samples presented both blue emission at 486 nm（Sr1）and green emission at 530 nm（Sr2）.However,the mechanoluminescent（ML）and afterglow spectra were consistent in the emission at 530 nm,which indicated that both emissions originated from Eu^2＋transition located at Sr2 sites.Comparing thechange of mechanoluminescent（ML）and afterglow intensity,we can conclude that the changes of mechanoluminescence performance are not only related to the traps but also related to its structural.At the same time,the ML intensity of Sr2SiO4∶Eu,Dy increased with the increase of mechanical load and the ML images of Sr2SiO4∶Eu,Dy can be observed by naked eyes,which suggested this phosphor can be applied as potential sensors to detect stress.Furthermore,combined with afterglow,thermoluminescence and ML properties,it can be inferred thatthe origin of ML is piezoelectricity-induced electroluminescence,that is,piezoelectricity impelled the trapped electrons from the traps and produce ML.