Supramolecular charge transfer emitters: increasing efficiency in the near-infrared

新的有机材料对于适应21世纪的功能、可持续和生物兼容技术的发展至关重要。支持有机发光二极管(OLED)的发光材料就是一个很好的例子，OLED是一种节能的设备，是薄、轻、灵活的现代显示器的基本组件。在光谱的近红外区域工作的有机发光二极管也具有极大的潜力，包括在医疗保健方面的新技术。例如，近红外有机发光二极管将被用于血氧检测皮肤贴片，以提供持续且非侵入性的氧气监测，这是护理新冠肺炎患者和英国老龄化人口的关键。然而，有机发光器件目前并不适合这种应用，因为有机发光材料在近红外的效率较低，这阻碍了设备的信号强度。为了解决这个问题，本项目的目的是开发在近红外区域高效的最先进的有机发光材料。最有前途的有机发光材料使用富电子和贫电子的分子，即所谓的施主-受主材料，具有热激活延迟发射。然而，由于缺乏结构控制，这些材料目前在近红外领域的效率较低。这种控制对于优化供体和受体分子之间的电子通信是必不可少的。在这里，研究分子间相互作用的超分子化学已经成熟。这个研究项目将利用超分子化学来优化施主-受主电子通信，开发新的分子结构来提高其近红外发射的效率，用于有机发光二极管。对这一新的超分子方法的全面科学理解将通过专业的光谱实验来建立结构-性质关系。这项工作将为化学家提供一幅供体-受体材料设计的新蓝图，使包括有机光电子学、催化和生物成像在内的广泛研究领域受益。新的发射体将用于制备荧光材料，超分子化学将再次成为将溶液转化为薄膜的效率的关键。从长远来看，这些材料将应用于近红外OLED设备，包括可穿戴医疗诊断，从而进一步提高该项目的社会经济影响。

New organic materials are critical to the advancement of functional, sustainable, and biocompatible technologies, fit for the 21st century. An excellent example are the emissive materials that underpin organic light-emitting diodes (OLEDs), devices which are energy-efficient and essential components of thin, lightweight, and flexible modern-day displays. OLEDs that operate in the near-infrared region of the spectrum also have fantastic potential, including for new technologies in healthcare. For example, near-infrared OLEDs would be used for blood oximetry skin patches, to provide continuous and non-intrusive oxygen monitoring, key to nursing Covid-19 patients and an ageing UK population. However, OLEDs are currently unsuitable for this application because the efficiency of organic emissive materials in the near-infrared is low, which hampers device signal strength. To address this problem, the aim of this project is to develop state-of-the-art organic emissive materials that are efficient in the near-infrared region.The most promising OLED materials use electron-rich and electron-poor molecules, so-called donor-acceptor materials that exhibit thermally activated delayed emission. However, these materials currently have low efficiencies in the near-infrared, owing to a lack of structural control. This control is essential to optimising the electronic communication between donor and acceptor molecules. Here, supramolecular chemistry, the study of interactions between molecules, is ripe for exploitation.This research project will use supramolecular chemistry to optimise donor-acceptor electronic communication, developing novel molecular architectures to boost the efficiency of their near-infrared emission, for OLEDs. A comprehensive scientific understanding of this new supramolecular approach will be realised through specialist spectroscopic experiments to establish structure-property relationships. This work will arm chemists with a new blueprint of design for donor-acceptor materials, benefiting a broad range of research fields, including organic optoelectronics, catalysis and bioimaging. The new emitters will be used to prepare fluorescent materials, where again supramolecular chemistry will be key in translating efficiency from solution to thin films. In the longer-term, these materials will be applied in near-infrared OLED devices, including for wearable medical diagnostics, thereby furthering the project's socioeconomic impact.