Circularly polarized thermally activated delayed fluorescence material based on chiral sulfur acceptors with AIE effect

Circularly Polarized Thermally Activated Delayed Fluorescence (CP-TADF) materials have wide applications in optoelectronics because of their attractive properties. However, CP-TADF molecular design based on point chirality has concentrated mainly on chiral carbon, the source of chiral elements is single. Here two new acceptors containing chiral sulfur atom: (R)-Br-2NSO and (S)–Br–2NSO are designed and synthesized, and by combining them with donor, two novel CP-TADF materials (R/S)–2NSO-DMAC are obtained. (R/S)–2NSO-DMAC emits blue-light at 471 nm with obvious aggregation-induced emission (AIE) property and high photoluminescence quantum yield (PLQY) up to 81 % in toluene. Circular dichroism (CD) and circularly polarized luminescence (CPL) spectra suggest that (R/S)–2NSO-DMAC have favourable CPL traits, with luminescence dissymmetry factor (|g_lum|) up to 4.0 × 10⁻⁴. Non-doped CP-OLED based on (−)-2NSO-DMAC emits sky-blue light at 495 nm, and achieves successfully circularly polarized electroluminescence with the electroluminescence dissymmetry factor (|g_EL|) up to 1.0 × 10⁻³ and maximum external quantum efficiency (EQE_max) up to 4.1 %.