Exploring Mechanoluminescence of Zinc Alkaline Earth Metal Oxysulfides from Fundamentals to Advanced Applications

Abstract

Mechanoluminescent (ML) materials convert mechanical stimuli into light emission, enabling applications in stress distribution visualization, structural health monitoring, biomechanical imaging, and sono-optogenetics. Achieving efficient and full-spectrum ML materials represents a long-standing challenge. Zinc alkaline earth metal oxysulfides, namely CaZnOS, SrZnOS, BaZnOS, and SrZn₂S₂O, have emerged as prominent contenders in this field due to their exceptional ML properties. These materials feature low-stress thresholds for emission activation, high ML intensity without the need for irradiation charging, and tunable spectra ranging from visible to near-infrared, thus advancing ML research and broadening application possibilities. Here, a comprehensive review of the significant advancements made in ML research on zinc alkaline earth metal oxysulfides over the past decade, encompassing synthesis, characterization, mechanisms, and promising applications is presented. Special attention is focused on addressing conflicting reports on ML generation conditions, recent progress in accurately characterizing ML performance, and understanding mechanical-to-optical conversion processes. Future directions in fundamental ML research and the challenges in translating these advancements into practical applications are also discussed.