Elucidating the mechanism for light emission in donor-acceptor functionalized, symmetry-broken triaryl methyl radicals and polyradicals

在这个项目中，我们将研究和揭开卤代三叔丁基自由基中导致其光致发光的跃迁。理论计算将与实验相辅相成并得到验证。我们将合成新的给体功能化和不对称的三苯基自由基和多自由基，以开辟原本对称性禁止的弛豫途径。这将有助于我们理解导致光发射的过程，并开发具有前所未有的短弛豫时间和高光致发光量子产率的高性能自由基发射体。为了寻找具有最大性能的体系，将使用量子化学计算来筛选不同取代的三叔丁基自由基。不同取代基的快速衰减率将使用不受限制的简化TD-DFT进行筛选，以识别具有大振子强度的系统。此外，我们将确定D0和D1态之间的锥形交点的最小能量，以获得关于非辐射衰变和转移速率的信息。为此，我们将发展一个无限制版本的洞-洞-Tamm-Dancoff近似密度泛函理论方法(HH-TDA)。

In this project, we will investigate and unravel the transitions in halogenated trityl radicals that lead to their photoluminescence. Theoretical calculations will be accompanied and validated by experiments. We will synthesize new donor-functionalized and asymmetric trityl radicals and polyradicals to open up otherwise symmetry-forbidden relaxation pathways. This will help us to understand the processes that lead to light emission and to develop high performance radical emitters with unprecedentedly short relaxation times and high photoluminescence quantum yields. To find systems with maximum performance, screening of differently substituted trityl radicals will be performed using quantum chemical calculations. Differently substituted radicals will be screened for fast decay rates using unrestricted simplified TD-DFT to identify systems with large oscillator strengths. Furthermore, we will determine the minimum energy of conical intersections between the D0 and D1-states to acquire information about non-radiative decay and transfer rates. For this purpose, we will developed an unrestricted version of the hole-hole-Tamm-Dancoff-approximated density functional theory method (hh-TDA).