CAREER: Nanophotonic Radiative Decay Rate Engineering for Stable Blue Organic Phosphorescence

非技术描述：使用有机发光材料的显示和照明技术正在成为液晶显示器和无机发光二极管（LED）照明的节能、通用替代品。然而，高效的蓝色磷光有机发光器件的工作寿命比绿色和红色磷光器件短20到45倍，这限制了它们的商业用途。该项目通过基础材料科学研究解决了这一重要的技术挑战，并采用光子纳米结构来提高高效蓝色有机发光材料的稳定性。此外，该项目还让公众参与一个互动的公共实验，由本科生和K-12学生建造，以测试发光材料的寿命，激发对这些材料的兴趣，并使研究项目的发现能够传达给学术界以外的受众。从事该研究项目的研究生和本科生研究人员有机会参加国际研究经验，以扩大他们的研究技能，促进国际科学合作，并获得发展中国家面临的技术挑战的全球视角。技术描述：高效有机发光器件使用磷光分子或表现出热激活延迟荧光的分子来允许三重态激子的辐射重组。然而，与高效的蓝色有机三重态发射材料相关的稳定性问题主要是由于三重态-三重态和三重态-极化子湮灭，这可能比三重态激子发射器在高亮度下的辐射衰减时间更快。该职业奖的研究部分旨在通过利用近场（即5-50 nm）发射体与纳米光子结构的局部电磁场之间的相互作用引起的Purcell效应引起的辐射衰减率增强，提高蓝色有机三重态发射体的光稳定性和电致发光稳定性。更快的辐射衰减速率允许三重态发射与三重态猝灭的非辐射途径竞争，从而提高发射材料的稳定性。尺寸和形状控制的电介质（例如，二氧化硅，氧化锌）和钝化等离子体（银和铝）纳米光子结构由一系列纳米制造技术制备。

Non-technical Description: Display and lighting technologies that use organic light-emitting materials are emerging as energy-efficient, versatile alternatives to liquid-crystal displays and inorganic light-emitting diode (LED)-based lighting. However, high-efficiency blue phosphorescent organic light-emitting devices exhibit operational lifetimes that are 20 to 45 times shorter than green and red organic phosphorescent devices, which limit their commercial use. This project addresses this important technology challenge through fundamental materials science research and employs photonic nanostructures to increase the stability of high-efficiency, blue organic light-emitting materials. In addition, the project involves the public in an interactive public experiment, built by undergraduate and K-12 students, to test the lifetime of light-emitting materials and to stimulate interest in these materials and to enable the findings of the research project to be communicated to audiences beyond the academic community. Graduate and undergraduate researchers working on the research project have opportunities to take part in international research experiences to expand their research skills, foster international scientific collaborations and gain global perspectives of the technical challenges faced by developing countries. Technical Description: High-efficiency organic light-emitting devices use either phosphorescent molecules or molecules that exhibit thermally-activated delayed fluorescence to allow radiative recombination from triplet excitons. However, there are stability problems associated with high-efficiency, blue organic triplet-emitting materials primarily due to triplet-triplet and triplet-polaron annihilation, which can occur faster than radiative decay times of triplet exciton emitters at high luminance. The research component of this CAREER award aims to increase the photostability and electroluminescence stability of blue organic triplet emitters by making use of radiative decay rate enhancements caused by the Purcell Effect arising from near-field (i.e., 5-50 nm) interactions between emitters and the local electromagnetic fields of nanophotonic structures. Faster radiative decay rates allow triplet emission to compete with triplet quenching non-radiative pathways and, thereby, improve the stability of the emitting material. Size- and shape-controlled dielectric (e.g., silica, zinc oxide) and passivated plasmonic (silver and aluminum) nanophotonic structures prepared from a range of nanofabrication techniques are employed.