【作者】 张寒露；

【导师】 董林；

【作者基本信息】 郑州大学 ， 材料学， 2016， 硕士

【摘要】 应力发光(Mechanoluminescence,ML)泛指在机械力作用下受力物体或周围介质发光的现象,常见于于各种固体受力过程,可分为摩擦发光和形变应力发光两大类。近年来,形变应力发光中的弹性形变应力发光(Elasto-ML,EML)由于具有可重复性强、发光强度与所受应力强度线性相关度高等特点成为了相关领域的研究热点。弹性应力发光材料可以实现无需外加电源的力-光转换,因而在机械结构件的应力分布可视化、建筑物应力实时无损监测分布系统、人机交互界面的应力分布传感等领域具有良好的应用前景。然而,目前弹性应力发光材料存在种类较少、系统研究不足、发光机理不明、探测功能单一、器件结构和测试系统欠缺等问题,这阻碍了其实际应用进程。针对弹性应力发光材料研究中存在的这些问题,本论文主要开展了如下几项工作:(1)采用高温固相法制备了两种高亮度ZnS:Mn2+和CaZnOS:Er3+弹性应力发光粉体材料,并使用构造了 PET基柔性复合薄膜应力发光器件,配合本课题组搭建的应力发光性能测试系统研究其应力发光性能。(2)系统研究了烧结温度、掺杂浓度对ZnS:Mn2+晶体结构和应力发光性能的影响,得到了使用ZnS和MnCO3为原料,真空高温固相法制备高亮度ZnS:Mn2+弹性应力发光粉体的较优化条件为:1 mol%的掺杂比例(Mn/Zn),1050～1150℃烧结3h。(3)研究发现高压电系数的纤锌矿型ZnS基质比低压电系数的闪锌矿型ZnS基质更利于ZnS:Mn2+的应力发光,由此引入了压电光子学和压电诱导电子脱陷模型解释ZnS:Mn2+的弹性应力发光机理。(4)研究了掺杂原料、烧结温度对CaZnOS:Er3+产物中基质物相组成的影响,结果表明以ErF3作为掺杂原料要比Er2O3更有利于单一基体相CaZnOS的生成,1050℃是制备CaZnOS:Er3+较为合适的烧结温度。(5)研究了 CaZnOS:Er3+的多功能发光特性,包括在380 nm紫外线激发下的下转换发光,980 nm红外线激发下的上转换发光,以及在滑动载荷作用下的应力发光;利用其弹性应力发光强度与所受应力大小的线性相关可以实现应力探测;利用Er3+上转换发光中2H11/2→4I15/2和4S3/2→4I15/2两个发射波段的荧光强度比率(FIR)实现了 303.15 K～603.15 K范围内温度的精确探测。(6)本文构造的柔性复合薄膜应力发光器件可以实现应力成像,使用基于它的应力成像系统,将其应用于了动态书写特征的光学数字化记录。更多还原

【Abstract】 Mechanoluminescence(ML)is a light emission process induced by the application of any mechanical stimuli on physical objects,whether the light may be emitted from the object being stimulated or the ambient medium,and generally the object is a solid.The ML appeared in solids could be classified into two basic categories,the tribo-ML and the deformation-ML.In recent years,the elastic-ML,as a type of deformation-ML,has attracted interests of researchers in ML-related field due to the merit of recoverable ML emission and the linear dependence of light emission intensity on the mechanical stress during the elastic-ML.Elastic-ML materials are capable of transducing mechanical stress into light emission without electrical power supply,therefore they show outstanding prospects of application in visualizing stress distribution in surfaces of machineries,in monitoring the stress condition in buildings,in mapping dynamic pressure in human-machine interaction,etc.However,currently few ML materials are found to be elastic-ML materials,and systematical researches on elastic-ML materials are insufficient.Moreover,there also exist other challenges in studies on elastic-ML materials,such as the luminescence mechanisms are ambiguous,the functionality of elastic-ML materials is simplex,the device structures based on elastic-ML materials are not universal,and the measurement system for elastic-ML and practical,which seriously impedes the practical application of elastic-ML materials.Aiming at promoting the solution of these problems,this dissertation presents related researches and results as follows:(1)Two kinds of elastic-ML powder materials with high ML brightness,ZnS:Mn2+ and CaZnOS:Er3+,were prepared through high temperature solid state reactions,laminated between flexible and transparent PET films to constitute flexible composite ML thin-film devices,and then their ML properties are characterized using ML test system built up by our research group.(2)The influences of the sintering temperature and doping concentration on the crystal structure and ML properties of prepared ZnS:Mn2+ powders are systemically investigated.It is found that proper reaction parameters for the solid state reaction to prepare ZnS:Mn2+ powders with high ML brightness materials is:1 mol%doping concentration(Mn/Zn),sintered under temperature of 1050～1150℃ for 3h,using ZnS and MnCO3 as raw materials.(3)It is found that wurtzite-type ZnS as the host material with higher piezoelectric coefficient is more conducive to the ML emission of ZnS:Mn2+ than sphalerite-type ZnS as the host material with lower piezoelectric coefficient,therefore piezo-photonics and piezoelectricity-induced electrons de-trapping model were introduced to elucidate the luminescence mechanism of elastic-ML of ZnS:Mn2+.(4)The influences of the doping raw materials and sintering temperature on the phase composition in the prepared CaZnvS:Er3+ powders were investigated.It is found that ErF3 as the doping raw material is more facilitative than Er2O3 for the unitary existence of CaZnOS phase in the sintered products,and 1050℃ is the proper sintering temperature for the preparation of CaZnOS:Er3+ through solid state reaction.(5)The multiple luminescent properties of prepared CaZnOS:Er3+were investigated,including its down-shifting luminescence under the excitation of 380 nm UV light,up-conversion luminescence under the excitation of 980 nm near infrared laser,and ML under the load of dynamic sliding stress.The elastic-ML property of CaZnOS:Er3+ was utilized to realize stress detection,and the up-conversion property was utilized to implement accurate temperature sensing.(6)A stress visualization system based on the as-fabricated flexible composite ML thin-film devices was built,and it is used to digitally record the handwriting features based on optical signals.更多还原