近红外长余辉荧光生物成像具有高信噪比，大生物组织穿透深度，免原位激发等优点而受到人们的广泛关注。Ni2+激活的镓酸盐材料是一类具有近红外二区发射的高效长余辉材料，有望成为新型荧光探针并应用于生物医学领域。目前，Ni2+激活镓酸盐长余辉纳米晶在可控制备和长余辉发光机理研究方面仍有待深入研究。本项目提出采用两步热分解法实现形貌均匀且具有高发光效率Ni2+激活镓酸盐纳米晶的可控制备；探索Ni2+掺杂镓酸盐纳米晶尺寸、表面结构以及内部陷阱中心对发光性能的影响规律；利用低温高分辨率荧光光谱和变温荧光光谱，揭示俘获和去俘获过程，深入研究长余辉发光机理；阐明稀土离子与Ni2+离子之间的能量传递机理，建立长余辉发光量子产率的评价方法。预期研制的纳米晶尺寸约20 nm，余辉时间≥1 h，筛选出高量子产率的Ni2+激活镓酸盐长余辉纳米晶1-2种，并展示其在生物组织和细胞成像领域的应用。

Owing to the merits of high signal-to-noise ratio, deep-imaging tissue penetration depths and free in-situ excitation, near-infrared persistent luminescence bioimaging has been gained extensive attentions. Ni2+ activated gallate is a family of persistent luminescence (PL) materials with second near-infrared window, which could service as excellent fluorescencent probes for biomedical applications. At present, deeply systematic study on the controllable preparation technology and PL mechanism of Ni2+ activated gallate PL nanocrystals (PLNCs) is still lacking. In this project, a two-step thermal decomposition method is used to realize the preparation of Ni2+ activated gallate PLNCs with uniform morphology and high luminous efficiency. The influence of Ni2+ activated gallate PLNCs’ size, surface structure and traps on luminescent properties will be explored. The trapping and de-trapping process will be revealed by low-temperature high resolution and temperature-independent fluorescence spectra, and the PL mechanism will be in-depth studied. The energy transfer process between rare earth and Ni2+ ions will be clarified. The evaluation methodology of PL quantum yield will be established. The expected size of PLNCs is about 20 nm, and the afterglow time more than 1 h. 1 or 2 kinds of PLNCs with high quantum yield will be screened out, and the application of Ni2+ activated gallate PLNCs in the field of biological tissue and cell imaging will be demonstrated.