Chiral Co-Assembly with Narrowband Multi-Resonance Characteristics for High-Performance Circularly Polarized Organic Light-Emitting Diodes.

A promising kind of ternary chiral co-assemblies with high PLQY, large dissymmetry factor (g lum ), and narrowband multi-resonance characteristics are achieved by codoped-thermal annealing treatments of achiral luminescent polymer F8BT, chiral inducers R/S-5011, and achiral FRET acceptor DBN-ICZ. The optimized co-assemblies (F8BT) 0.9 -(R/S-5011) 0.1 -(DBN-ICZ) 0.005 display narrowband yellow emission with full-width half maximum (FWHM) of 37 nm, PLQY of 79%, and intense CPL signals with |g lum | of up to 0.26. Meaningfully, solution-processed CP-OLEDs by using those ternary chiral co-assemblies as emitting layer are successfully fabricated, which display yellow circularly polarized electroluminescence (CPEL) with EQE max of 4.6% and g EL of up to 0.16. The corresponding Q-factor could reach up to 7.36 × 10 -3 , which is the highest of all the reported CP-OLEDs. Moreover, the devices also exhibit excellent comprehensive device performance with low V on of 7.0 V, high L max of about 25 000 cd m -2 , extremely low efficiency roll-off with EQE of 4.3% at 10 000 cd m -2 , as well as narrowband EL with FWHM of only 39 nm. The proposed ternary co-assembly strategy in fabricating CP-OLED provides the possibility to achieve high comprehensive device performance such as balancing high EQE and large g EL value, as well as narrowband emission, high brightness and low efficiency roll-off simultaneously.