Mechanoluminescence (ML) materials with the ability to convert mechanical stimulate into visible light signals have enabled visualized mechanics sensing. To this point, stress sensing based on ML color is preferred over that based on ML intensity in terms of both sensing reliability and visual sensitivity. In this work, a ratiometric dual‐emitting ML strategy to realize the stress‐sensitive ML color variation, where the Lanthanide/transition‐metal combination is adopted to build the dual‐activator ML system is proposed. The difference in electronic configuration between Lanthanide and transition‐metal ions leads to the significant discrepancy in the response of corresponding luminescence kinetics to the instantaneous change of local crystal field environment induced by stress, which plays a key role in the strategy. This strategy establishes a new general path for the design of novel ratiometric ML materials.

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As one of important members of refractory materials, tungsten phosphide (WP) holds great potential for fundamental study and industrial applications in many fields of science and technology, due to its excellent properties such as superconductivity and as-predicted topological band structure. However, synthesis of high-quality WP crystals is still a challenge by using tradition synthetic methods, because the synthesis temperature for growing its large crystals is very stringently required to be as high as 3000 °C, which is far beyond the temperature capability of most laboratory-based devices for crystal growth. In addition, high temperature often induces the decomposition of metal phosphides, leading to off-stoichiometric samples based on which the materials’ intrinsic properties cannot be explored. In this work, we report a high-pressure synthesis of single-crystal WP through a direct crystallization from cooling the congruent W–P melts at 5 GPa and ∼ 3200 °C. In combination of x-ray diffraction, electron microscope, and thermal analysis, the crystal structure, morphology, and stability of recovered sample are well investigated. The final product is phase-pure and nearly stoichiometric WP in a single-crystal form with a large grain size, in excess of one millimeter, thus making it feasible to implement most experimental measurements, especially, for the case where a large crystal is required. Success in synthesis of high-quality WP crystals at high pressure can offer great opportunities for determining their intrinsic properties and also making more efforts to study the family of transition-metal phosphides.