Aggregation-induced emission phenanthroline derivatives for ultrahigh color purity deep blue OLEDs with CIEx≤0.15 and CIEy≤0.08 and low efficiency roll-off.

Due to the limited molecular design strategy, the development of ultrahigh color purity deep blue aggregation-induced emission (AIE) emitters with excellent photophysical and electroluminescence performances is still facing challenges at present. In this study, an effective design strategy for deep blue emitters is proposed, which can improve the performances of non-doped organic light-emitting diodes (OLEDs) by adjusting the link mode of the phenyl bridge and utilizing the steric hindrance effect of the rigid plane. Two new emitters, 3BCzPT and 4BCzPT, were obtained with phenanthroline acceptor and carbazole donor for deep blue emitting OLEDs. Particularly, 3BCzPT has been proven to have AIE characteristics through photophysical properties. Non-doped OLEDs with 3BCzPT demonstrate prominent electroluminescence (EL) performances reaching a maximum current efficiency (CEmax) of 6.3 cd A−1 and maximum external quantum efficiency (EQEmax) of 3.81%, well as ultrahigh color purity with Commission Internationale de L'Eclairage (CIE) coordinates of (0.151, 0.053). While the parameters of non-doped OLED based 4BCzPT are 4.2 cd A−1, 1.96% and (0.147, 0.082). Both emitters exhibit narrow EL spectra with the full-width at half maximum (FWHM) of 56 and 52 nm. • A strategy to construct deep blue AIE emitters with D-π-A-π-D configuration was proposed. • Highly twisted configurations are beneficial to the formation of weak intra/intermolecular interaction. • Non-doped OLEDs provided ultrapure deep blue emission with CIE x ≤0.15 and CIE y ≤0.08. • This feasible strategy can enrich the design strategy of deep blue emitters and further extend their application in OLEDs. [ABSTRACT FROM AUTHOR]