无阈值应力发光材料LiNbO3:Pr3+的晶格缺陷分析及其应力发光机理研究

Mechanoluminescence (ML) is luminescence that is induced by mechanical stimuli. The most important form of ML, elasticoluminescence, has attracted considerable attention because it is a promising candidate for applications such as artificial intelligence, damage diagnosis and information storage, etc. In 2017, a new type of thresholdless elastic ML material, LiNbO3:Pr3+ (LNO), was successfully developed, which could predict and quantify the risk level for micro strains below 300 μst. Its development suggests that this multi-piezo material could be investigated as a multifunctional material with multiple electro-mechano-optical effects. However, the previous studies mainly focused on the material development and ML regulation, which was still lack of detailed analysis on the lattice defects and ML mechanism in LNO. The goal of this proposal is to determine the thresholdless ML mechanism of LNO in detail and investigate the lattice defects of LNO by combing the theoretical calculation and defect analysis techniques. We also intend to study the thresholdless ML properties by using comparative analysis of lattice defects in LNO. Once defined, we envisage that our research not only will help to improve the ML intensity of LNO, but also will greatly promote the further development in single-cell imaging and precision tests.

应力发光是将机械能转化为光能的一种效应。其中弹性应力发光能够成功实现非破坏性应力可视化检测，所以在人工智能，灾害检测等各领域展现出广阔的应用前景。最近一种无阈值应力发光材料LiNbO3:Pr3+ (LNO)被成功开发，这种材料具有高度敏感的应力发光性能，能无阈值检测极小的应变（小于300 µst），是一种兼具压电性和压光性的理想多功能材料。然而，之前的相关研究着重于材料开发和应力发光强度调控，缺乏对LNO结构中晶格缺陷的详细分析和应力发光过程的机理解析。针对这一问题，本申请拟对LNO的无阈值应力发光性能进行检测，同时结合理论计算和缺陷分析技术来探明LNO的晶格缺陷的状态和分布，以此确定LNO在应力发光过程中的电子移动和发光过程，最终总结出其无阈值应力发光机理。本项目的实施将对LNO的应力发光强度提升，以及微应变条件下的多种技术应用如单细胞级别生物显像和精密应力分析等起到重要推动作用。

应力发光是将机械能转化为光能的一种效应。其中弹性应力发光能够成功实现非破坏性应力可视化检测，所以在人工智能，灾害检测等各领域展现出广阔的应用前景。本项目拟对LiNbO3基的无阈值弹性应力发光性能进行应力发光检测，同时结合理论计算和缺陷分析技术来探明其应力发光机理。在项目执行过程中，项目负责人团队成功实现对纯相LiNbO3系列应力发光材料的合成，并创新性地采用Mxene前驱体合成法实现了板状LiNbO3基应力发光材料的制备，实现了对应力发光材料的微型化和精细化的突破。同时团队针对其应力发光强度和重复性做了深入研究，根据日光照射以及热处理的两种方式确认了LiNbO3基应力发光材料中陷阱结构以及压电性能对应力发光特性的产生的不同影响，利用Na离子替换等方式实现了应力发光强度和重复性的大幅度提升。同时针对应力发光机理解析方面，团队利用第一性原理计算，结构精修，热致发光技术等手段，确定了LiNbO3体系中能带间隙，晶体场变化和压电效应对应力发光特性的显著影响，并首次实现了陷阱电子完全清除后的高重复性应力发光特性。该项目的成功实施确认了材料陷阱结构对于应力发光性能影响的复杂性，同时证明了应力发光陷阱的填充可以摆脱传统光励起模式，而通过压电特性等方式也能够实现有效填充。该项目结果为未来高重复性及高稳定性应力发光材料的应用探索提供了重要的开发依据和指导方案。