Chiral Sulfonyl Binaphthalene-Based Thermally Activated Delayed Fluorescence Materials for Circularly Polarized Electroluminescence

Chiral emitters capable of producing circularly polarized luminescence (CPL) with high dissymmetry factors (g) are crucial for circularly polarized organic light-emitting diodes (CP-OLEDs) and 3D display. Herein, sulfonyl binaphthalene is incorporated as both electron acceptor and chiral source into three pairs of thermally activated delayed fluorescence (TADF) enantiomers, (R/S)-BPSTCZ, (R/S)-BPSDMAC, and (R/S)-BPSPXZ, for the first time, combining tert-butylcarbazole, 9,9-dimethyl-9,10-dihydro-acridine and phenoxazine electron donors, respectively. These TADF compounds exhibit tunable emissions spanning from deep blue to green, accompanied by high photoluminescence quantum yields. Due to the large distorted angles caused by two sulfonyl units, all enantiomers exhibit pronounced CPL with |gPL| factors of up to 6.0 x 10-3 in doped films. The corresponding CP-OLEDs display good performances with external quantum efficiencies of up to 28.5% and notable |gEL| factors of up to 8.8 x 10-3, surpassing most CP-OLEDs based on chiral TADF materials. By introducing the (R/S)-sulfonyl binaphthalene units, three pairs of thermally activated delayed fluorescence enantiomers show emissions from deep blue to green with dissymmetry factors |gPL| of up to 6.0 x 10-3. The circularly polarized organic light-emitting diodes (CP-OLEDs) achieve external quantum efficiency of up to 28.5% and circularly polarized electroluminescence with |gEL| factors of up to 8.8 x 10-3. image