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

从广受好评的TSB资助的无上装项目开始，我们将致力于开发一套聚合物材料，所有这些聚合物都具有高三重态能量，这将使全磷光多层聚合物发光器件(PLED)能够专门用于固态照明应用。由Thorn Lighting与CDT和Durham牵头的无上装项目已经证明，可以很容易地制造出提供25 lm/W高质量白光的全解决方案处理的PLED面板。这里的关键是使用荧光蓝色发射器以及磷光绿色和红色发射器来产生三白光谱。计算表明，为了进一步提高效率，达到40 lm/W或更高，器件必须使用全磷光发射器。这就要求对多层器件结构中使用的材料进行根本性的改变，使得所有层(聚合物)必须具有足够高的三重态能量，以防止蓝色荧光粉的猝灭。这样的聚合物还不存在。在这个研究项目中，我们向设计和合成高三重态空穴传输、电子传输和双极(发射极宿主)材料迈出了第一步。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，从而产生新一代材料。关键的构建块已被确定为这项工作的起点，几个有希望的主题已获得Thorn Lighting的专利(通过Project Toless和达勒姆的其他工作)。在项目期间，我们不会自己制造发射器；作为无上装项目的一部分，达勒姆已经开发了一个新的蓝色荧光粉家族，并将与达勒姆的J.A.G.威廉姆斯博士合作探索新的荧光粉。这里我们重点介绍蓝色荧光粉的主体材料和传输层材料。随着新材料的设计、合成和表征，我们将利用达勒姆(Durham)开发的多层制造技术(也是最近获得专利的)，探索最适合高效率蓝光和白色发射的器件架构。此外，将使用新的光谱学(在达勒姆开发)和与柯达合作开发的模型(与布鲁内尔大学的克里斯·温斯康姆教授继续合作)对多层结构中的三重态激子迁移进行详细分析。这将使我们能够研究发射层内三重态激子限制的想法，这样传输层就不会充当猝灭位置。这将使传输层的设计和合成变得更加简单。随着这项工作的进展，管理团队将在项目第一年结束时做出关键决策。我们的目标是加快该项目期间生产的材料的新工业化。这将通过索恩对项目管理团队的投入来实现，并且该项目将与项目TOPDRAWER的继任者项目TOPDRAWER并行运行。前景看好的新材料组合可以快速进入Project TOPDRAWER，用于印刷试验和开发全磷光白色PLED面板。蓝色荧光粉主体材料的开发对荆棘照明将有机固态照明商业化的计划至关重要，他们将通过为该项目提供最大可能的支持来加快这一领域的研究。他们承诺支持这一项目，为该项目提供15万英镑的资金，以减少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.