Acridin-9(10H)-one-based blue thermally activated delayed fluorescence materials: improvement of color purity and efficiency stability

Accelerating PLQY and RISC rates in deep-blue TADF materials with the acridin-9(10H)-one acceptor by tuning the peripheral groups on carbazole donors

“…S1(b) in the ESI†), implying that these molecules may have very good amorphous stability with relatively high glass transition temperatures ( T g ). 2,23 This is reasonable considering their high molecular weights.…”

“…The important intermediate 3,6-DF-AD was synthesized according to a literature method. 23,34 The target compounds were then prepared through a nucleophilic substitution reaction between different donor intermediates and the acridone intermediate 3,6-DF-AD in the presence of cesium carbonate in anhydrous N , N -dimethylformamide (DMF) at 165 °C. The products were thoroughly purified via repeated column chromatography and recrystallization to reach high purity for use in spectroscopy and OLED studies.…”

“…3,6-DF-AD was first synthesized according to literature methods. 23,34 A mixture of 3,6-DF-AD (200 mg, 0.65 mmol), carbazole or corresponding carbazole derivative (1.43 mmol), cesium carbonate (847 mg, 2.6 mmol) and 15 mL dry N , N -dimethylformamide (DMF) was stirred at 165 °C under a nitrogen atmosphere. After cooling to room temperature, the mixture was poured into water and the precipitate was filtered under reduced pressure and purified by column chromatography on silica gel using DCM as the eluent to afford a solid, which was then deeply purified by repeated recrystallization from CHCl 3 /CH 3 OH to afford the pure product.…”

Carbonyl‐Containing Thermally Activated Delayed Fluorescence Emitters for Narrow‐Band Electroluminescence

“…In 2022, Li and co-workers reported acridone-based derivatives named 2,7-DtBuCz-AD, 3,6-DtBuCzAD, 3,6-DMAC-AD, and 3,6-DMAC-AD-CF3, respectively. [26] The comparisons of decay curves for 2,7-DtBuCz-AD and 3,6-DtBuCzAD indicates that the introduction of donors on the C3 and C6 positions is beneficial for TADF properties. Small steric hindrance of carbazole and large ΔE ST (0.36 eV) contribute to the small k RISC of 0.3 × 10 3 s À 1 of 3,6-DtBuCzAD, 3,6-DMAC-AD, and 3,6-DMAC-AD-CF3 with 9,9-dimethyl-9,10-dihydroacridine (DMAC) as strong donors with large steric hindrance exhibit well-separated HOMO/LUMO distributions and distinct TADF properties (k RISC = 2.2/4.6 × 10 6 s À 1 ).…”

“…In 2022, Li and co‐workers reported acridone‐based derivatives named 2,7‐DtBuCz‐AD, 3,6‐DtBuCzAD, 3,6‐DMAC‐AD, and 3,6‐DMAC‐AD‐CF3, respectively [26] . The comparisons of decay curves for 2,7‐DtBuCz‐AD and 3,6‐DtBuCzAD indicates that the introduction of donors on the C3 and C6 positions is beneficial for TADF properties.…”