High triplet energy polymers for blue phosphorescent, solution-processable multilayer PLEDs to develop solid-state lighting

从备受赞誉的tsb资助的TOPLESS项目开始，我们将致力于开发一套聚合物材料，所有这些材料都具有高三重态能量，这将使全磷光多层聚合物发光器件（led）能够专门用于固态照明应用。由Thorn Lighting与CDT和Durham牵头的TOPLESS项目已经证明，全溶液处理的PLED面板可以很容易地制造出25 lm/W的高质量白光，没有外耦合。这里的关键是使用荧光蓝色发射器与磷光绿色和红色发射器一起产生三白光谱。计算表明，要使效率进一步提高，达到40 lm/W或更高，必须利用全磷光发射器制造器件。这就要求在多层器件结构中使用的材料发生根本性的变化，这样所有层（聚合物）都必须具有足够高的三重态能量，以防止蓝色荧光粉的猝灭。这种聚合物还不存在。在这个研究项目中，我们迈出了设计和合成高三重态空穴输运、电子输运和双极（发射器宿主）材料的第一步。材料将使用一系列光谱技术进行充分表征。设备将被制造和测试，导致新一代的材料。关键的构建模块已经被确定为这项工作的起点，并且一些有前途的图案已经与Thorn Lighting一起获得专利（通过Project TOPLESS和Durham的其他工作）。在这个项目中，我们不会制造排放者本身；作为toppless项目的一部分，一种新的蓝色荧光粉家族已经在达勒姆开发出来，新的荧光粉将与达勒姆的J. a . G. Williams博士合作探索。本文重点讨论了蓝色荧光粉的寄主层和传输层材料。随着新材料的设计、合成和表征，我们将探索最适合高效蓝光和白色发射的设备架构，利用杜伦大学开发的多层制造技术（最近也获得了专利）。此外，多层结构中三重激子迁移的详细分析将使用新光谱（在达勒姆开发）和与柯达合作开发的模型，并继续与布鲁内尔大学的克里斯·温斯科姆教授合作。这将使我们能够研究在发射层内的三重态激子约束的想法，使输运层不作为淬火点。这将使传输层的设计和合成更加简单。在项目第一年结束时，管理团队将根据这项工作的进展做出关键决策。我们的目标是快速跟踪在这个项目中制造的新型工业化材料。这将通过Thorn对项目管理团队的投入以及该项目将与TOPLESS项目的后续项目（即TOPDRAWER项目）并行运行的事实来实现。有前途的新材料组可以迅速进入TOPDRAWER项目，用于印刷试验和开发全磷光白色PLED面板。蓝色荧光粉的主体材料的开发对于索恩照明将有机固态照明商业化的计划至关重要，他们将通过给予该项目最强有力的支持来加速该领域的研究。他们承诺为该项目提供15万英镑的资金支持，减少EPSRC的资金。

Leading on from the highly acclaimed TSB-funded Project TOPLESS, we will work towards developing a materials set of polymers, all of which posses high triplet energies, which will allow all-phosphorescent, multi-layer polymer light-emitting devices (PLEDs) to be made specifically for use in solid-state lighting applications. Project TOPLESS, lead by Thorn Lighting with CDT and Durham has demonstrated that all-solution-processed PLED panels giving high quality white light at 25 lm/W without out-coupling can be readily made. The key here was the use of a fluorescent blue emitter along with phosphorescent green and red emitters to generate a tri-white spectrum. Calculations show that to make a further step change in efficiency, towards 40 lm/W or more, devices must be made utilising all-phosphorescent emitters. This dictates radical changes to the materials used in the multi-layer device structure, such that all the layers (polymers) must have sufficiently high triplet energies to prevent quenching of the blue phosphor. Such polymers do not yet exist. In this research project we take the first steps towards the design and synthesis of high triplet hole-transport, electron-transport and ambipolar (emitter host) materials. Materials will be fully characterised using a range of spectroscopic techniques. Devices will be fabricated and tested, leading on to new generations of materials. Key building blocks have been identified as starting points for this work and several promising motifs have been patented with Thorn Lighting (via Project TOPLESS and through other work at Durham). During the project we shall not make the emitters themselves; a new family of blue phosphors has been developed in Durham, as part of the TOPLESS project and new phosphors will be explored in collaboration with Dr J. A. G. Williams in Durham. Here we focus on the materials for hosts and transport layers for blue phosphors. Along with the design, synthesis and characterisation of new materials, we will explore device architectures best suited to high efficiency blue and white emission, exploiting multi-layer fabrication techniques developed in Durham (also recently patented). Further, detailed analysis of triplet exciton migration within multilayer structures will be made using both novel spectroscopy (developed in Durham) and modelling developed in a collaboration with Kodak and continued in collaboration with Prof Chris Winscom at Brunel University. This will enable us to investigate ideas of triplet exciton confinement within an emitter layer such that transport layers do not act as quenching sites. This would then make the design and synthesis of transport layers much more simple. Critical decision points following the progress of this work will be made by the management team at the end of the first year of the project.We aim to fast-track new industrialisation of materials made during this project. This will be achieved by input from Thorn on the project management team and the fact that this project will run in parallel with the successor to Project TOPLESS, namely Project TOPDRAWER. Promising new materials sets can be rapidly feed into Project TOPDRAWER for printing trials and development of an all-phosphorescent white PLED panel. The development of host materials for blue phosphors is so vital to Thorn Lighting's plans to commercialise organic solid-state lighting that they will accelerate research in this area by giving the strongest possible support to this project. They have committed to support this project by contributing 150,000 to the cost of the project, reducing the EPSRC's funding by this amount.