Forced Intergrowth of NaYS₂ Phase in Sulfur-Rich Environments with Fluorescence Remodeling of Upscaled Full-Spectrum

Optimization of the host lattice is a novel strategy to achieve efficient up-conversion luminescence (UCL) with multi-peak full-spectrum emission. Herein, lattice optimization is performed in a non-vacuum sulfur-rich environment, where the ultra-low phonon energy NaYS₂ heterogeneous phase is forced to intergrow, which overcomes the limitations of the conventional vacuum preparation method and achieves high-efficient UCL. Remarkably, the lattice sites are preferentially occupied by S²⁻, which causes lattice distortion and generates layered NaYS₂/Y₂O₂S hybrid crystalline with high inversion asymmetry to reconfigure excitation mechanism and exhibit distinct luminescence centers at the multi-peak full-spectrum. Moreover, owing to longer lifetime of excited state energy levels of Er³⁺ after lattice modification and ordered segregation of Er³⁺ in the YS₆ layer restricting the negative energy exchange process, the luminescence intensity is increased by about six times, and the remodeling of full-spectrum-efficient UCLs is realized. This work reports an innovative approach for lattice optimization and a facile preparation of ternary sulfides, which provides a new direction for achieving highly efficient UCLs with promising applications in biomedical imaging, near-infrared detection, and temperature sensing synergy.