Exploration of Zn(II) complexes for efficient phosphorescence and TADF

Zn(II) 配合物高效磷光和 TADF 的探索

• 批准号: 404381916
• 负责人: Professorin Dr. Christel M. Marian
• 金额: --
• 依托单位: Institut für Theoretische Chemie
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/404381916?language=en
• 关键词: Exploration; Zn; II; complexes; efficient

The investigation of transition metal complexes as emitters is of fundamental im¬portance for the development of highly innovative applications in lighting and display technology. Because the electron-hole-recombination process produces ca. 75% triplet states, it is highly desirable to exploit these states for luminescence. In the last decade, luminescent Cu(I) complexes have seen a phoenix-like rise, with many proof-of-concept applications in OLEDs. Their attractive¬ness is mainly due to the absence of low-energy d-d* states which could give rise to very fast non-radiative decay and to the fact that many of these complexes show thermally activated delayed fluorescence (TADF), providing an emission mecha¬nism bypassing the spin-forbidden T1→S0 transition by thermal re-population of the singlet excited state S1 with subse¬quent fluorescence S1→S0. The beauty of this mech¬anism is that it re¬moves the necessity of strong spin–orbit coupling (SOC) and greatly increases the overall radiative rate constant kr. Interestingly, Zn(II) complexes, which also exhibit a d10 electron configuration, have received very little attention as emitters to exploit triplet excitons by phosphorescence or TADF. Based on our previous achievements with regard to photoactive d10 transition metal carbene complexes and our preliminary results, we aim to close this gap. This collaborative project proposal combines the synthetic and spectroscopic expertise of the Steffen group and the theoretical expertise of the Marian group to develop Zn(II) complexes for efficient luminescence exploiting triplet excitons, either via phosphorescence or via TADF, by employing carbene ligands of varying π-acceptor strength in various coordination geometries to enable LLCT and LMCT states with strong SOC. We will study environmental influences on the properties of the long-lived excited states, establish theoretical models for their photokinetic excited state behavior, and demonstrate the use of selected candidates in first proof-of-concept applications.

过渡金属配合物作为发光体的研究对于照明和显示技术中高度创新应用的开发具有根本重要性。因为电子空穴复合过程产生了Ca。75%的三重态，因此高度期望利用这些态用于发光。在过去的十年中，发光Cu（I）配合物出现了凤凰般的增长，在OLED中有许多概念验证应用。它们的吸引力主要是由于不存在可引起非常快的非辐射衰变的低能量d-d* 态，以及这些络合物中的许多显示热激活延迟荧光（TADF）的事实，从而通过单重激发态S1与随后的荧光S1→ S 0的热再布居提供绕过自旋禁戒T1→ S 0跃迁的发射机制。这种机制的美妙之处在于，它消除了强自旋轨道耦合（SOC）的必要性，并大大增加了总辐射速率常数kr。有趣的是，锌（II）配合物，也表现出d10电子配置，已经收到很少的关注，作为发射体利用三重态激子的磷光或TADF。基于我们以前在光活性d10过渡金属卡宾配合物方面的成就和我们的初步结果，我们的目标是缩小这一差距。该合作项目提案结合了Steffen小组的合成和光谱专业知识以及Marian小组的理论专业知识，以开发Zn（II）络合物，用于通过磷光或通过TADF利用三重态激子进行有效发光，通过采用不同π-在各种配位几何结构中的受体强度，使LLCT和LMCT状态具有强SOC。我们将研究环境对长寿命的激发态，建立其光动力学激发态行为的理论模型，并展示在第一概念验证应用中使用所选候选物。