Zusammenfassung
The dinuclear Ag(I) complex has been designed to show thermally activated delayed fluorescence (TADF) of high efficiency. Strongly electron-donating terminal ligands are introduced to destabilize the d orbitals of the Ag+ ions. Consequently, the orbitals distinctly contribute to the HOMO, whereas the LUMO is localized on the bridging ligand. This ensures charge transfer character of the lowest ...
Zusammenfassung
The dinuclear Ag(I) complex has been designed to show thermally activated delayed fluorescence (TADF) of high efficiency. Strongly electron-donating terminal ligands are introduced to destabilize the d orbitals of the Ag+ ions. Consequently, the orbitals distinctly contribute to the HOMO, whereas the LUMO is localized on the bridging ligand. This ensures charge transfer character of the lowest excited singlet S-1 and triplet T-1 states. Accordingly, a small energy gap Delta E(S-1-T-1) is obtained, being essential for TADF behavior. Photophysical investigations show that at ambient temperature the complex exhibits TADF reaching a quantum yield of Phi(PL) = 70% with the decay time of only tau = 1.9 mu s, manifesting one of the fastest TADF decays observed so far. Such an outstanding TADF efficiency is based on a small value of Delta E(S-1-T-1) = 480 cm(-1) combined with a large transition rate of k(S-1 -> S-0) = 2.2 X 10(7) s(-1).