石墨烯与稀土氧化物纳米晶复合材料的制备与发光性质的研究

In recent years, graphene has received extensive attention because of their excellent physical and chemical properties.Among them, the luminescence properties of graphene quantum dots also been reported.?Graphene quantum dot has stable structure, easily dispersed in solvent and good biocompatibility. However, the luminescence properties of graphene quantum dot is unstable,and the luminescence mechanism is also not clear. The research in this field just reaches a basic stage. On the other hand, as an excellent matrix material, graphene can be used to synthesize composite with the other inorganic oxide,and its performance of the resulting composite material has been significantly improved. But so far, there is no report about the luminescence properties of the composites base on graphene. This project intends to use rare earth oxides as starting materials, using wet chemical method combined preparation of composite materials, and to study the luminescence properties. It can be optimized its luminescent performance according to controll the morphology and particle size of the composite material and doping. By studying characteristics of nanocomposites doping and quenching, the process of energy transfer and rare earth ions sensitized of composite material emitting, the luminescence mechanism of graphene materials can be explored. Base on these, such composite materials with different luminescent characteristics can be developed and extend the scope of its application.

近年来，石墨烯因其优异的物理化学性质而受到了广泛的关注。其中，石墨烯量子点的发光性质也被报道。与传统半导体量子点相比，石墨烯量子点的结构稳定，易于分散在溶剂中，生物相容性好，但其发光性质不稳定，发光机理不明确，其研究尚处在起步阶段。另一方面，石墨烯作为一种优异的基质材料可以与其它无机氧化物复合，所得到的复合材料的性能得到了明显的改善。但目前为止还没有关于石墨烯基复合材料的发光性质的报道。本项目拟使用稀土氧化物为对象，使用湿化学法与石墨烯相结合制备复合材料，研究其发光性质。通过对复合材料的形貌和颗粒尺寸进行控制，并对其进行掺杂，使其发光性能得到最优化。通过研究纳米复合材料的掺杂与猝灭的特性，复合材料发光的能量传递及稀土离子敏化发光过程，可以对石墨烯材料的发光机理进行探索。在此基础上可以开发这类复合材料不同的发光特性，扩宽其应用范围。

石墨烯复合发光材料的研究在石墨烯功能化研究中尚处于起步阶段。本项目使用湿化学法制备了多种发光材料与石墨烯的复合材料，探索制备工艺并研究其发光性质，并对发光机理尝试进行探索。首先以氧化物Y2O3:Eu3+，Gd2O3:Eu3+/Dy3+,ZnO:Eu3+，MgO:Eu3+为研究对象与氧化石墨烯复合，探索了最佳的制备条件，发现氧化石墨烯的加入在一定程度上改善了材料的发光效果但会影响发光材料本身的结晶性能。然后使用YVO4:Eu3+及YBO3:Eu3+/Tb3+为研究对象与氧化石墨烯复合并优化制备工艺，发现使用一步水热法合成的复合物样品比两步法具有更好的发光性能，石墨烯的加入减小了发光材料样品的颗粒尺寸并提高了分散性，其中在石墨烯/YBO3:Eu3+复合样品中观测到了石墨烯复合后在250-450 nm的紫外-可见范围内的吸收增加，说明存在石墨烯吸收能量传递给发光中心的能量传递途径。最后使用不同制备方法制备了SrB6O10:Eu3+，BaAl12O19:Mn2+等不同形貌的发光材料并研究其真空紫外发光性质。总结石墨烯复合发光材料后对样品发光效果有正反两个方面的影响。好处体现在两点：一是石墨烯的加入减小了发光材料样品的颗粒尺寸并提高了分散性；二是石墨烯加入后提高了样品在紫外-可见范围内的吸收使得该范围内激发的发光强度得到了增加。缺点也有两点：一是石墨烯的加入影响了样品的结晶性能，二是石墨烯加入导致样品本身的颜色变深，影响发光强度。本项目现有结果表明，通过改进制备工艺及优化工艺参数，石墨烯复合发光材料有望在LED及长余辉发光材料领域内得到进一步的应用。