Functional Nanoparticles for Lighting Materials and Antibacterial Coatings

在本项目中，我们有三个主要目标：首先，我们的初步工作表明，可以用离子液体作为起始原料制备质量更好、尺寸更小的含Eu 2+的纳米颗粒，这对照明功能材料非常重要。与目前用于生产这些材料的熔融法相比，我们的新方法节省了大量的原材料，能源和时间。此外，这种方法还可以制备新的纳米发光材料，这是目前尚不清楚的。另一种方法是开发用于抗菌涂层的功能材料。该项目的第三个目标是研究非常小的Eu2+掺杂颗粒，这些颗粒适合回答这些离子的发光特性是否可以随着颗粒尺寸而改变的问题。事实上，这将导致一种新的战略，用于开发多种用途的功能材料。这些研究的理想候选物是未掺杂或掺杂有二价镧系元素（Ln 2+）离子的氟化物、氧化物和硫化物，这是由于它们的扩展带隙、防腐剂或半导体特性。然而，目前可用的合成方法不适合于在小纳米尺度下制备这些晶格。特别是对于Ln 2+掺杂的晶体，水和其他常规溶剂的氧化性质构成了主要障碍。这一僵局的最终解决方案是通过离子液体（IL）辅助合成方法提供的。由于高极性和配位环境，离子液体能够容易地溶解反应物并稳定颗粒表面，避免不期望的晶体生长。与水相比，离子液体能够稳定二价状态的镧系元素离子，使得Ln 2+颗粒能够直接沉淀，并且避免在T > 1000°C和人工气氛下的合成后还原退火步骤。

In this project we aim for three main objectives: firstly Eu2+ containing nanoparticles which are very important for lighting functional materials can be produced with ionic liquids as starting materials with a much better quality and a smaller size as our preliminary works show. Compared to the melting method which is currently used for the production of these materials our new method save a lot of raw materials, energy and time. Furthermore, new nanosized luminescence materials can be prepared by this method which is not known yet. Another approach is the development of functional materials for antibacterial coatings. A third goal of this project is the investigation of extremely small Eu2+ doped particles which are suitable to answer the question if the luminescence properties of these ions can be changed with the particle size. This would in fact lead to a new strategy for the development of functional materials for many purposes. Ideal candidates for these studies are fluorides, oxides and sulfides, undoped or doped with divalent lanthanide (Ln2+) ions, due to their expanded bandgap, antiseptic or semiconductor character. Nevertheless, the currently available synthesis methods are not appropriated for the preparation of these lattices in a small nanoscale. Especially for Ln2+-doped crystals, the oxidative nature of water and other conventional solvents consist a major obstacle. The ultimate solution of this impasse is offered by ionic liquid (IL)-assisted synthesis methods. Because of the high polar and coordinative environment, ILs are able to easily solve reactants and stabilize the particle surface, avoiding undesired crystal growth. In contrast with water, ILs are able to stabilize lanthanide ions in the divalent state, enabling the direct precipitation of Ln2+ particles and avoiding post-synthetic reducing annealing steps at T > 1000°C and artificial atmosphere.