Atomic Layer Deposition coating of quantum dots in beads

Nanoco是英国唯一的量子点（QD）制造商和供应商，量子点是一种只有几纳米大小的微小半导体晶体。量子点表现出不寻常的和有趣的能源效率的性质，是令人兴奋的商业在许多快速增长的市场，包括电致发光显示器，固态照明，太阳能电池，生物技术和生物医学。量子点与传统器件相比具有许多优势，包括更高的性能、更高的效率和显著降低的环境影响。利用其独特特性的新市场已接近商业开发。目前商业应用中的大多数QD含有镉（Cd），这是一种对环境有害的有毒重金属。新的立法正在防止/最大限度地减少全球镉的使用，日本公司将不会利用任何镉技术。生物医学应用需要不含重金属的点。Nanoco已经开发出专有的合成路线，以大量生产与Cd基系统具有同等性能和稳定性的不含重金属的点。然而，量子点目前需要进行复杂和昂贵的表面改性，以提高其在空气中的稳定性。对于商业开发来说，客户（通常是大型电子公司）可以轻松处理这些点是至关重要的。另一种确保稳定性的方法是使用原子层沉积（ALD）用氧化物涂覆含有点的珠粒。Nanoco已经与利物浦大学进行了原理ALD试验的证明，但现在需要在工业规模扩大之前，使用改进的反应器开发内部工艺。无镉量子点的ALD涂层需要详细的研究和开发。该项目的最终结果将是基于氧化物ALD的工业可扩展工艺的后期原型。

Nanoco is the sole UK manufacturer and supplier of state of the art quantum dots (QDs), tiny semiconductor crystals only a few nanometers in size. QDs exhibit unusual and interesting energy efficient properties that are exciting commercially in many fast growing markets including electroluminescent displays, solid state lighting, solar cells, biotechnology and biomedicine. The QDs’ many advantages over conventional devices include higher performance, increased efficiency and significantly lower environmental impact. New markets to exploit their unique properties are close to commercial exploitation. The majority of QDs currently in commercial applications contain cadmium (Cd), a toxic heavy metal which is damaging to the environment. New legislation is preventing/minimising the use of Cd worldwide and Japanese companies will not exploit any Cd-based technology. Of necessity biomedical applications require heavy metal free dots. Nanoco has developed proprietary synthetic routes to produce heavy metal free dots of equivalent performance and stability to Cd-based systems in large quantities. However the QDs currently need to undergo intricate and expensive surface modification to improve their stability in air. For commercial exploitation it is essential that the dots can be easily handled by customers (typically giant electronic companies). An alternative process ensuring stability is to coat beads containing the dots with an oxide using Atomic Layer Deposition (ALD).Nanoco has carried out proof of principle ALD trials with Liverpool University but now needs to develop a process in-house with a modified reactor, prior to industrial scale-up. The ALD coating of Cd-free QDs requires detailed investigation and development. The end result of this project would be the late stage prototype of an industrial scalable process based on ALD of oxides.