TY - JOUR
T1 - Intramolecular locking and coumarin insertion
T2 - a stepwise approach for TADF design
AU - Paredis, S.
AU - Cardeynaels, T.
AU - Brebels, S.
AU - Deckers, J.
AU - Kuila, S.
AU - Lathouwers, A.
AU - Van Landeghem, M.
AU - Vandewal, K.
AU - Danos, A.
AU - Monkman, A. P.
AU - Champagne, Benoit
AU - Maes, W.
N1 - Publisher Copyright:
© 2023 The Royal Society of Chemistry.
PY - 2023/10/18
Y1 - 2023/10/18
N2 - Three novel TADF (thermally activated delayed fluorescence) emitters based on the well-studied Qx-Ph-DMAC fluorophore are designed and synthesized. The photophysical properties of these materials are studied from a theoretical and experimental point of view, demonstrating the cumulative effects of multiple small modifications that combine to afford significantly improved TADF performance. First, an extra phenyl ring is added to the acceptor part of Qx-Ph-DMAC to increase the conjugation length, resulting in BQx-Ph-DMAC, which acts as an intermediate molecular structure. Next, an electron-deficient coumarin unit is incorporated to fortify the electron accepting ability, affording ChromPy-Ph-DMAC with red-shifted emission. Finally, the conjugated system is further enlarged by ‘locking’ the molecular structure, generating DBChromQx-DMAC with further red-shifted emission. The addition of the coumarin unit significantly impacts the charge-transfer excited state energy levels with little effect on the locally excited states, resulting in a decrease of the singlet-triplet energy gap. As a result, the two coumarin-based emitters show considerably improved TADF performance in 1 w/w% zeonex films when compared to the initial Qx-Ph-DMAC structure. ‘Locking’ the molecular structure further lowers the singlet-triplet energy gap, resulting in more efficient reverse intersystem crossing and increasing the contribution of TADF to the total emission.
AB - Three novel TADF (thermally activated delayed fluorescence) emitters based on the well-studied Qx-Ph-DMAC fluorophore are designed and synthesized. The photophysical properties of these materials are studied from a theoretical and experimental point of view, demonstrating the cumulative effects of multiple small modifications that combine to afford significantly improved TADF performance. First, an extra phenyl ring is added to the acceptor part of Qx-Ph-DMAC to increase the conjugation length, resulting in BQx-Ph-DMAC, which acts as an intermediate molecular structure. Next, an electron-deficient coumarin unit is incorporated to fortify the electron accepting ability, affording ChromPy-Ph-DMAC with red-shifted emission. Finally, the conjugated system is further enlarged by ‘locking’ the molecular structure, generating DBChromQx-DMAC with further red-shifted emission. The addition of the coumarin unit significantly impacts the charge-transfer excited state energy levels with little effect on the locally excited states, resulting in a decrease of the singlet-triplet energy gap. As a result, the two coumarin-based emitters show considerably improved TADF performance in 1 w/w% zeonex films when compared to the initial Qx-Ph-DMAC structure. ‘Locking’ the molecular structure further lowers the singlet-triplet energy gap, resulting in more efficient reverse intersystem crossing and increasing the contribution of TADF to the total emission.
UR - http://www.scopus.com/inward/record.url?scp=85175579484&partnerID=8YFLogxK
U2 - 10.1039/d3cp03695b
DO - 10.1039/d3cp03695b
M3 - Article
C2 - 37888766
AN - SCOPUS:85175579484
SN - 1463-9076
VL - 25
SP - 29842
EP - 29849
JO - Physical Chemistry Chemical Physics
JF - Physical Chemistry Chemical Physics
IS - 43
ER -