Elucidating a complete picture of exciton dynamics in operating quantum-dot light-emitting diodes

量子点发光二极管（QLED）作为节能、色纯和柔性光源，在显示、照明和通信技术中具有广阔的应用前景。目前，QLED的性能受到高电流下的效率滚降和长期操作中的器件退化的阻碍。QLED的进一步发展需要深入了解器件操作中的基本过程。然而，由于缺乏原位/操作表征方法，在操作QLED的超快电荷和激子动力学仍然不清楚。在这里，该项目旨在超越最先进的方法，并创建一套超快光谱工具包，以阐明操作QLED中激子动力学的时空分辨图像。我将实现a）操作时间分辨瞬态吸收（TA），B）操作时空TA显微镜，和c）电泵浦的时间分辨TA测量上的QLED的完整堆栈。我将获得激子解离，激子扩散和电子注入动力学的定量见解。最后，对量子发光二极管的效率下降和退化提供了新的机理解释。该项目涵盖了光学，材料科学和器件物理学的学科，结合了主机组在超快光谱学方面的专业知识和研究人员在QLED方面的专业知识。研究员将获得互补的技能和知识，以达到专业成熟。这些成果将增加对纳米材料和LED的基本理解，促进QLED的优化以满足实际需求。该项目将为各种LED提供广泛适用的工具包。该项目的成功实施将促进东道国组织在光电子领域的竞争力。从长远来看，QLED的潜在商业化有望降低电力消耗，促进欧洲的可持续发展。

Quantum-dot light-emitting diodes (QLEDs) are promising as energy-saving, color-pure, and flexible light sources for display, lighting, and communication techniques. At present, the performance of QLEDs is hindered by the efficiency roll-off at high currents and the device degradation in long-term operations. Further development of QLEDs demands an in-depth understanding of the fundamental processes in device operations. However, due to the lack of in-situ/operando characterization methods, the ultrafast charge and exciton dynamics in operating QLEDs is still not clear. Here, the project aims to go beyond the state-of-the-art methodologies, and create a set of ultrafast spectroscopic toolkits to elucidate a spatio-temporal resolved picture of exciton dynamics in operating QLEDs. I will realize a) operando time-resolved transient absorption (TA), b) operando spatio-temporal TA microscopy, and c) electrically-pumped time-resolved TA measurements on full stacks of QLEDs. I will gain quantitative insights into exciton dissociation, exciton diffusion, and electron injection dynamics. Finally, new mechanistic interpretations on the efficiency roll-off and degradation of QLEDs will be provided. The project covers the disciplines of optics, material science, and device physics, combining the host group's expertise in ultrafast spectroscopy, and theresearcher's expertise in QLEDs. The fellow will acquire complementary skills and knowledge to reach professional maturity. The outcomes will increase the fundamental understanding of nanomaterials and LEDs, facilitating the optimization of QLEDs towards practical requirements. The project will yield a widely-applicable toolkit for various LEDs. Successful implementation of this project will promote the competitiveness of the host organization in the field of optoelectronics. In the long run, the potential commercialization of QLEDs is expected to reduce electricity consumption and promote sustainable development in Europe.