Mechanoluminescence (ML) has been extensively studied at MPa level, but the rate-dependent ML kinetics at GPa level remains poorly understood. Scientists from HPSTAR, Shanghai Advanced Research Institute, CAS and Institute of Fluid Physics, CAEP, have discovered an interesting oscillatory mechanoluminescent phenomenon under compression from ambient pressure to ~10 GPa at the critical compression rate. This research, published in Nature Communications, uncovers the temporal characteristics of self-recoverable ML and provides insight into understanding the rate-dependent ML kinetics in the mechanical-photon energy conversion, conducive to the design of ML-based optoelectronic devices.

Self-recoverable ML enables continuous photon emission through mechanical work, offering promising applications in optoelectronics and pressure sensing. The effect of pressure on the ML performance has been mainly considered in previous studies, yet the time and rate dependence of ML kinetics has been ignored. It leads to the limitations in the development of time-dependent functions in the ML devices. This is because the mechanism that underlies the complex ML emission process in the mechanical-photon energy conversion remains elusive, and the detailed information on the rate-dependent ML kinetics is still lacking.

Caption: Rate-dependent mechanoluminescence (ML) in dynamic response to rapid compression

In this work, we present systematic studies of ML at the GPa level by a combination of dynamic diamond anvil cells and time-resolved optical measurements. It shows rate-dependent mechanoluminescent kinetics under rapid compression at the GPa level. A novel oscillatory mechanoluminescent phenomenon, i.e., cyclic light emission with a series of oscillatory peaks, is revealed under ramp compression up to 10 GPa at the critical rates of ~1.2-1.5 GP/s. The temperature-dependent characteristic time indicates the limitation of the mechanoluminescent kinetics in the dynamic response to rapid compression. This work offers a perspective for the underlying mechanoluminescent mechanism that is conducive to the design and development of high-performance ML materials in materials science.

在力致发光（Mechanoluminescence, ML）领域，自恢复型力致发光材料能够在连续机械刺激下发射光子，实现机械能和光能的转换。此前，材料设计的重点大多聚焦于在 MPa 压力范围内压强对力致发光性能的影响，对 ML 强度与波长的研究较多。然而却忽略了力致发光过程对时间和速率的依赖关系，以及对机械-光能转换中复杂的动力学过程和背后的物理机制仍然理解不透彻。来自北京高压科学研究中心的林传龙研究员和合作者，利用时间分辨荧光光谱和动态加载dDAC，揭示了在快速压缩过程中Mn 掺杂的 SrZnOS 表现出速率依赖的共振力致发光动力学特性，为深入理解力致发光的背后机制提供了新视角。相关工作以《Oscillatory mechanoluminescence of Mn2+-doped SrZnOS in dynamic response to rapid compression》为题发表在《自然通讯》期刊上。