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

从备受赞誉的TSB资助的项目TOPLESS开始，我们将致力于开发一系列聚合物材料，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（PLED）专门用于固态照明应用。由Thorn Lighting与CDT和达勒姆公司领导的TOPLESS项目已经证明，可以很容易地制造出在25 lm/W下提供高质量白色光而没有外耦合的全溶液处理的PLED面板。这里的关键是使用荧光蓝色发射体沿着磷光绿色和红色发射体来产生三白光谱。计算表明，为了使效率进一步阶跃变化，达到40 lm/W或更高，必须利用全磷光发射体制造器件。这决定了多层器件结构中使用的材料的根本变化，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磷光体的淬灭。这样的聚合物还不存在。在这个研究项目中，我们采取了第一步的设计和合成的高三重态空穴传输，电子传输和双极（发射器主机）材料。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。关键的构建块已被确定为这项工作的起点和几个有前途的图案已与荆棘照明专利（通过项目无顶和通过其他工作在达勒姆）。在这个项目中，我们不会自己制造发光体;一个新的蓝色磷光体家族已经在达勒姆开发出来，作为TOPLESS项目的一部分，新的磷光体将与J.A. G.达勒姆的威廉姆斯。在这里，我们专注于蓝色荧光粉的主机和传输层的材料。沿着新材料的设计、合成和表征，我们将探索最适合高效蓝光和白色发光的器件架构，利用达勒姆开发的多层制造技术（最近也获得专利）。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建模，并继续与布鲁内尔大学的Chris Winscom教授合作，对多层结构内的三重态激子迁移进行详细分析。这将使我们能够调查的想法，三重态激子限制在发射极层，使运输层不作为淬火网站。这将使传输层的设计和合成更加简单。管理团队将在项目第一年结束时制定关键决策点。我们的目标是快速跟踪项目期间制造的材料的新工业化。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）并行运行来实现。有前景的新材料组可以快速地输入到TOPDRAWER项目中，用于全磷光白色PLED面板的印刷试验和开发。蓝色荧光粉基质材料的开发对于Thorn Lighting的有机固态照明商业化计划至关重要，他们将通过为该项目提供最强有力的支持来加速该领域的研究。他们承诺支持这个项目，为项目的费用提供15万美元，减少了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.