Development of Fully-Printed and Eco-Friendly Light-Emitting Diodes Using Organometal Hybrid Perovskite Emitters

摘要：非技术：发光二极管已经发展成为重要的商业产品。据信，它们将取代传统的白炽灯和荧光灯，用于显示器和照明灯具。尽管发光二极管的亮度和稳定性在过去十年中有了很大提高，但每个二极管的成本仍然相对较高。这已成为制约其广泛市场渗透的瓶颈。该项目旨在开发一种革命性的技术，可以使用可扩展的打印工艺来制造高产量的大面积发光二极管。由于对多层器件架构的需求，现有的发光二极管不能被打印。相反，所提出的器件利用了极其简化的单层器件结构。这种独特的方法开辟了一条获得全印刷发光二极管的新途径，其中每一个制造步骤都可以通过印刷来执行。该项目将专注于材料化学和工艺开发，最终将导致在刚性和柔性衬底上制造发光二极管显示器和光面板。这些进步将大大降低发光二极管产品的成本，同时在多个应用领域实现更大的节能，特别是在需要大面积和漫射光的领域，如固态照明、信息显示器和照明墙纸。技术：新一代发光二极管基于有机金属杂化钙钛矿，这是一种新兴的半导体材料，可以很容易地溶解在有机溶剂中，并在溶剂挥发后结晶成发光薄膜。将钙钛矿与聚合物混合，以控制所得到的发光薄膜的结晶动力学和形貌。第一个研究任务是优化发光钙钛矿晶体在聚合物基质中的成核和生长，获得发光应用所需的最佳钙钛矿形貌。最佳的形态结构将通过测量复合材料的光电性能并确定其效率和亮度来确定。这将允许表征材料的不同结构和性能之间的关系，并设计科学的模型来描述合成过程。一旦完全确定了钙钛矿材料和聚合物之间的结构和性质关系，其结果将被用作制造各种颜色的LED的科学基础；以及提高这些器件的环境稳定性。该项目的最后一步将是研究钙钛矿聚合物溶液的流变行为，并优化加工技术，以生产均匀的大面积发光薄膜。将同时研究工艺分辨率，以允许创建像素大小特征。这项工作将允许在市场上建立一种新型的发光技术。此外，这项工作还将加强对钙钛矿型发射体结构-工艺-性能关系的基本了解。这些知识对于合理设计和优化钙钛矿型发光二极管，以实现大面积、低成本的显示器和光面板是至关重要的。

Abstract:Non-Technical:Light-emitting diodes have evolved as important commercial products. They are believed to replace traditional incandescent and fluorescent light bulbs for displays and lighting luminaires. While the brightness and stability of light-emitting diodes have greatly improved over the past decade, cost per diode still remains relatively high. This has become a bottleneck limiting their wide market penetration. This project aims to develop a revolutionary technology that can employ scalable printing processes to fabricate large area light-emitting diodes with high throughput. No existing light-emitting diodes can be printed due to the demand for a multilayer device architecture. In contrast, the proposed devices utilize an extremely simplified single-layer device structure. Such a distinctive approach opens up a novel path towards obtaining fully printed light-emitting diodes, in which every single fabrication step may be performed by printing. The project will focus on the material chemistry and process development that will eventually lead to the manufacturing of light-emitting diode displays and light panels on both rigid and flexible substrates. Such advancements will greatly reduce the cost of light-emitting diode products, while allowing for greater energy savings in multiple application fields especially where large area and diffused light are both desired such as: solid state lighting, information displays and illuminated wallpapers.Technical:The new generation light-emitting diodes are based on organometal hybrid perovskites, an emerging class of semiconducting materials that can be readily dissolved in an organic solvent and crystalized into luminescent thin films after solvent evaporation. The perovskites are mixed with a polymer to control the crystallization dynamics and morphology of the resulting light-emitting thin films. The first research task is to optimize the nucleation and growth of light-emitting perovskite crystals in polymer matrices, and obtain the optimal perovskite morphology for light-emitting applications. The optimal morphological structure will be determined by measuring the opto-electronic properties of the composite and determining the efficiency and brightness. This will allow the characterization of relationships between different structures and properties of the materials and design scientific models to describe the compositing process. Once the structure property relations between the perovskite materials and polymers have been fully determined the results will be used as a scientific basis to make LEDs of various colors; as well as improving the environmental stability of those devices. The final step of the project will be investigating the rheological behaviors of the perovskite polymer solutions and optimize the processing techniques to produce uniform, large area light-emitting thin films. The process resolution will simultaneously be investigated to allow pixel size features to be created. This work would allow for establishing a novel type of light-emitting technology on the market. In addition the work will enhance the fundamental understanding of the structure-process-property relationship of perovskite emitters. Such knowledge is crucial for the rational design and optimization of perovskite light-emitting diodes for achieving large area and low cost displays and light panels.