Enhanced Fluorescent OLEDs, through Triplet Fusion

这个项目显然专注于理解有机发光器件的一个最基本的方面，到目前为止，人们还很少认识到它的重要性。通过CDT，我们已经证明了OLED器件中高达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，如果我们还没有完全理解的话。通过阐明三重态融合机制并证明在正确的三重态能级下0.50单线态产率是可能的，我们的目标是构建能够从荧光发射器获得0.62内部量子效率的器件。这将为OLED的显示和照明性能带来真正的变化。我们将与CDT一起努力开发一种新的设备架构，以充分利用这种可能性。这将是一项极富冒险精神的应用科学。我们还将与九州大学合作，研究蒸发装置中的小分子系统。一系列最先进的光谱技术将被使用，这些技术在达勒姆大学最发达，也是最独特的，以充分阐明支撑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，但仍然知之甚少。我们将确定三重态聚变的单线态产率是如何由分子的能级控制的。此外，我们还将确定系统间高激发态三重态交叉到单重态歧管的效率，我们相信这一进一步的过程也有助于光学实验和OLED器件的整体单重态良率。与CDT一起，将开发一种基于聚合物二元体的新型设备，其中三重态融合最大化，旨在生产效率接近磷光器件的荧光oled。通过这种方法，我们可以生产出高效率的蓝色荧光器件，而不会产生与磷光系统相关的短寿命。这将是OLED设备的一个重大变化。该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英镑来抵消项目的EPSRC成本，另外还有30,000英镑用于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.