基于激光驱动波动的弹性应力发光动力学研究

Elasto-mechanoluminescence (EML) is a sort of non-destructive luminescence when solids are driven by mechanic force in the elastic deformation range, and is promising in vast of potential applications in the area of non-invasive distributed passive sensory of defect detection and stress visualization. However, due to the lack of research on the fast processes of carriers and other excited state species during EML, the mechanism of EML has not yet been well understood, which becomes the crux obstacle for the enhancement of EML efficiency, and hence hinders the development of defect detection and stress visualization with high efficiency and high resolution. To solve this problem, this project focuses on the EML of ZnS:Mn series materials. We propose a route to produce nanosecond-scaled dynamic high pressure loading by pulsed laser ablation effects, so as to generate a nanosecond-scaled tunable synchronized mechanical vibration wave to trigger transient EML. Combined with time-resolved spectroscopy, we will study the excited state dynamics of carrier generation, separation, capture, transitions, composite and energy transfer process under mechanical nanosecond-scaled short pulse excitation, to clarify the mechanism of stress defects on EML efficiency and improve the dynamic model of piezoelectric induced charge bombardment. Guided with the mechanism and dynamic model, it will be helpful to synthesis high-brightness nano-scaled EML materials, and provide both theoretical guidance and technical support for the design and preparation of high performance EML devices.

弹性应力发光是固体在弹性范围内机械受力下产生非破坏性发光的现象，在无源无损分布式缺陷检测和应力可视化传感等方面具有巨大的潜在应用。然而，由于缺少发光过程中载流子或激发态快速过程的研究结果，应力发光机理迄今尚未得到可靠解释，是制约当前该类材料发光性能的进步和相关高性能高分辨快速缺陷探测及应力可视化传感的关键问题。针对此问题，本项目以ZnS:Mn体系为研究对象，提出利用脉冲激光剥蚀效应产生纳秒量级的动高压加载，实现纳秒短脉冲可控同步应力触发，结合时间分辨光谱技术研究纳秒短脉冲机械力激励下载流子产生、分离、俘获、跃迁、复合和能量传递等激发态动力学过程，阐明缺陷对应力发光效率的调控机理，完善压电基质诱导电荷轰击的动力学模型，指导相关材料的设计与合成，提高纳米弹性应力发光材料的能量转换效率，为高性能弹性应力发光器件的设计与制备提供理论指导与技术支撑。

对外界环境的灵敏感知是实现人工智能系统精确规划与执行的前提，而机器触觉远远滞后于其他类型感知能力的发展，研究和发展高分辨率、高灵敏度、快速响应的应力传感技术，完善机器触觉拟生感知能力，对于发展面向微尺度应用的人工智能系统至关重要。.本项目面向微尺度应用的人工智能系统，利用脉冲激光剥蚀动高压加载探索了应力发光的发光动力学过程，结合电子自旋共振波谱等技术研究了材料应力激发后的载流子分离、弛豫等激发态过程，并探索材料缺陷对应力发光效率的调控机理；通过系统研究应力发光动力学过程，深入理解应力发光本质机理和影响因素，建立和优化弹性应力发光动力学模型，研究探索通过缺陷调控设计和制备高性能应力发光材料的途径，并进而指导高亮度纳米弹性应力发光材料的设计与制备；在此基础上，探索发展高分辨率、高灵敏度、实时响应的大规模光电传导的应力传感成像技术，构建微尺度复合应力成像器件，开发多种类型基于应力发光材料的新颖柔性光电器件，在基于应力发光的本征可拉伸全透明自供能触觉拟生器件及集成器件、超高亮度水驱动自供能传感与显示器件、基于光学信号传导的柔性可拉伸物理不可克隆函数等方面做出了有特色的创新性工作，在人机接口、触觉拟生领域具有重大的潜在应用前景和科学意义。