Cr3+激活高效远红光石榴石荧光材料的研究

可覆盖700-780 nm波段的远红光pc-LED（荧光粉转换的LED）在自然光合成、物质光谱学检测、光控植物栽培和光治疗等领域具有迫切需求，但高效远红光荧光材料缺乏，限制了上述应用。Cr3+是远红光荧光材料常用的发光中心，其发光效率受热激活过程影响显著，亟待探寻抑制热激活、提高发光效率的途径。申请人基于前期研究基础和位型坐标模型，提出通过增加晶场强度和减弱电子-声子耦合来抑制热激活的思想，拟开展Cr3+激活钙镥钪镁硅石榴石体系的高效远红光荧光材料的研究，已观察到该体系的发光强度随晶场强度的增加而显著提高，展示出具有高效远红光发射的诱人潜力。研究热激活能、热激活速率、发光效率与晶场强度和电子-声子耦合强度的依赖关系以及它们随基质组分、晶格参数的变化规律，实现材料组分优化，获得高效远红光荧光材料并提供材料设计的核心方法，促进远红光pc-LED的发展和应用。

Phosphor converted far-red LEDs (pc-LEDs) covering 700-780 nm spectral region are required urgently in artificial natural light sources, substance measurement based on spectroscopy, photo-morphogenesis, phototherapy and so on. However, the deficiency of the efficient far-red phosphors limits their pc-LED applications. Cr3+ is most used as a luminescence center in the far red emitting phosphors, in which the emission efficiency is influenced notably by thermal activation. A way to suppress the thermal activation and to achieve a high emission efficiency is required urgently. Based on previous work and configuration coordinate model, the applicant propose an idea for suppressing thermal activation by increasing crystal field strength and reducing electron-phonon coupling strength. The Cr3+ activated efficient far-red Ca-Lu-Sc-Mg-Si garnet phosphors will be studied, in which a pronounced enhancement of luminescence with the increase of crystal field strength has been observed, exhibiting an attractive potential for the achievement of a high emission efficiency. Hence, the dependence of thermal activation energy, thermal activation rate and emission efficiency on crystal field strength and electron-phonon coupling strength and their variations with phosphor compositions, lattice parameters will all be studied. Finally, the phosphor compositions are optimized. A highly efficient far-red phosphor could be achieved and a key method for design of highly efficient far-red phosphors could be provided so as to stimulate the development of far-red pc-LED and their applications in various fields.