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

• Applicants: Professor Dr. Christoph Bannwarth; Professor Dr. Alexander Kühne
• Subject Area: Preparatory and Physical Chemistry of Polymers ; Synthesis and Properties of Functional Materials
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 500226157

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).

• DFG Programme: Research Grants