Revealing energy transfer mechanisms and accelerating intelligent detection: Cr3+ and Ni2+ co-doped Lu2CaMg2Si3O12 phosphors for NIR applications†

The challenges of low blue light absorption, reduced luminous efficiency, and low thermal stability are critical issues confronting near-infrared II (NIR-II) phosphors, which significantly hinder their applications in food testing, medical imaging, and various other fields. Herein, an energy transfer strategy was adopted to enhance blue light absorption by introducing Cr³⁺ into Lu₂CaMg₂Si₃O₁₂:Ni²⁺, thereby enhancing their luminescence properties, including quantum efficiency and thermal stability. Given the superior energy transfer efficiency of Cr³⁺ → Ni²⁺, the quantum efficiency of Lu₂CaMg₂Si₃O₁₂:Cr³⁺,Ni²⁺ was increased from 23.0% to 32.6%, and the thermal stability improved by 18%, as compared to Lu₂CaMg₂Si₃O₁₂:Ni²⁺. Furthermore, the Dexter's model was employed to systematically analyze the energy transfer mechanism of transition metal ions. In addition, due to the difference in the temperature response of Cr³⁺ and Ni²⁺, the thermometry performance of this phosphor was studied. Importantly, a pioneering method for food components detection based on the convolutional neural network model was proposed, demonstrating a 100% detection success rate. This research not only propels the development of novel blue-light-excitable NIR-II phosphors but also contributes to the advancement of intelligent lighting technologies.