Enhanced Fluorescent OLEDs, through Triplet Fusion

这个项目显然专注于了解有机发光器件最基本的方面之一，这一点到目前为止还很少被认识到如此重要。通过CDT，我们已经证明了来自OLED设备的高达37%的光来自三重态融合，这本身就是一个绝对基本的激子过程，如果根本不能很好地理解的话。通过阐明三重态融合的机制，并证明在正确的三重态能级下，单重态的产额为0.50是可能的，我们的目标是建立能够从荧光发射体获得0.62的内部量子效率的器件。这将使OLED在显示和照明方面的性能发生真正的变化。我们将与CDT一起努力开发一种新的设备架构，以充分利用这一可能性。这将是一项极具冒险精神的应用科学。我们还将与九州大学在蒸发设备中的小分子系统方面进行合作。一系列最先进的光谱技术将被用来全面阐明支持三重态三重态湮灭和三重态融合的光物理过程，这是有机材料中一些最基本的激子过程，但仍知之甚少。我们将确定三重态融合的单线态产量如何受到分子能级的控制。此外，我们还将确定上激发态三重态系统间交叉到单重态流形的效率，我们认为这一进一步的过程也有助于光学实验和OLED器件的总单线态产量。与CDT合作将开发一种基于聚合物二元组的新器件，其中三重态融合最大化，并旨在生产效率接近磷光器件的荧光OLED。通过这种方式，我们可以生产高效率的蓝色荧光器件，而不需要与磷光系统相关的短寿命。这将是OLED设备的重大变革。这个项目得到了剑桥显示技术公司的全力支持，他们将提供45,000 GB来抵消项目的EPSRC成本，并提供另外30,000 GB的专门为该项目开发的新材料，以及用于建模和项目管理的进一步资源。

This project is clearly focused on understanding one of the most fundamental aspects of organic light emitting devices, which as yet is little recognised as being so important. With CDT we have shown that up to 37% of light coming from an OLED device arises from triplet fusion, in itself an absolutely fundamental excitonic process which if not at all well understood. By elucidating the triplet fusion mechanism and demonstrating that 0.50 singlet yield is possible with correct triplet energy levels we aim to build devices that could attain internal quantum efficiencies of 0.62 from fluorescent emitters. This would provide a real step change in OLED performances both for displays and lighting. Together with CDT we shall work to develop a new device architecture to fully exploit this possibility. This will be a highly adventurous piece of applied science. We will also collaborate with Kyushu University on small molecule systems in evaporated devices. A range of state of the art spectroscopic techniques will be used, most developed in and unique to Durham, to fully elucidate the photophysical process underpinning triplet triplet annihilation and triplet fusion, some of the most fundamental excitonic processes in organic materials but still poorly understood. We will determine how singlet yield from triplet fusion is controlled by energy levels of the molecule. Further, we shall also determine the efficiency of upper excited state triplet inter system crossing to the singlet manifold, a further process which we believe also contributes to the overall singlet yield both in an optical experiment and in an OLED device.Together with CDT will will develop a novel device based on a polymer dyad where triplet fusion is maximised and aim to produce fluorescent OLEDs with efficiencies approaching those of phosphorescent devices. In this way we can produce blue fluorescent devices of high efficiency without the short lifetime associated with phosphorescent systems. This would be a major step change for OLED device. This project has the full support of Cambridge Display Technology who will provide £45,000 to off set the EPSRC cost of the project and another £30,000 in new materials developed specifically for this project and further resource for modelling and project management.