Spiro donor–acceptor TADF emitters: naked TADF free from inhomogeneity caused by donor acceptor bridge bond disorder. Fast rISC and invariant photophysics in solid state hosts

Abstract

The molecular photophysics of 10-phenyl-10H,10′H-spiro[acridine-9,9′-anthracen]-10′-one (ACRSA) are used as an ideal molecule to probe how external factors affect the TADF and rISC mechanisms.

Understanding the internal heavy-atom effect on thermally activated delayed fluorescence: application of Arrhenius and Marcus theories for spin–orbit coupling analysis

“…1B). Such rotamers play a key role in the TADF photophysics, 19,[25][26][27][28] as the 1 CT-state energy and 3 CT-1 CT energy gap (DE 1CT-3CT ) are dependent on the y value. Such yrotamers with high deviation from the optimal 901 value and high 1 CT-energy emit in the blue region in the very early prompt fluorescence (PF) region and late DF, whereas y-rotamers close to 901 correspond to low 1 CT-energy, late-PF and early-DF emissions (Fig.…”

Laplace Transform Fitting as a Tool To Uncover Distributions of Reverse Intersystem Crossing Rates in TADF Systems

“…These emitters were chosen to showcase the effect of different D–A linkages; while DMAC-TRZ has a flexible C–N bridging bond, ACRSA contains a rigid spiro carbon atom that hinders almost all motion between D and A. 33 As a consequence, ACRSA molecules all have near-identical molecular geometry in film and a very narrow distribution of k rISC rates that is nearly identical in both hosts. Interestingly, the peak of the distribution is also unchanged for ACRSA in the two different hosts ( Figure S6 ), confirming the recently reported invariance it possesses to host environment, 33 in absolute contrast to DMAC-TRZ .…”

“… 33 As a consequence, ACRSA molecules all have near-identical molecular geometry in film and a very narrow distribution of k rISC rates that is nearly identical in both hosts. Interestingly, the peak of the distribution is also unchanged for ACRSA in the two different hosts ( Figure S6 ), confirming the recently reported invariance it possesses to host environment, 33 in absolute contrast to DMAC-TRZ .…”

1,4-Bis(trifluoromethyl)benzene as a new acceptor for the design and synthesis of emitters exhibiting efficient thermally activated delayed fluorescence and electroluminescence: experimental and computational guidance

“…This observation shows that compound 2AC-2CF 3 Ph is characterized by two 3 LE D states apparently having pp* and np* character as was reported for 10-phenyl-10H, 10 0 H-spiro[acridine9,9 0 -anthracen]-10 0one. 43,44 A pp* 3 LE D value of ca. 3.19 eV and an np* 3 LE D value of ca.…”