Efficient and stable deep-blue narrow-spectrum electroluminescence based on hybridized local and charge-transfer (HLCT) state

Two phenanthroimidazole-acridine derivatives ( DPM and TDPM ) were designed and synthesized for deep-blue organic light-emitting diode (OLED). Twisted combined rigid structures with hybridized local and charge-transfer (HLCT) state properties enable them to achieve excellent OLED performance. Non-doped OLEDs based on DPM and TDPM show decent deep-blue narrow-spectrum emission with Commission International de L’Éclairage (CIE) coordinates of (0.157, 0.053) and (0.158, 0.045), as well as maximum external quantum efficiency (EQE max ) of 4.0% and 2.6%, respectively. More importantly, OLEDs based on TDPM exhibit a smaller efficiency roll-off (12%) than that of DPM (35%) at high brightness (820 cd m −2 for DPM and 893 cd m −2 for TDPM, respectively). Overall, our work provides a molecular design strategy of HLCT materials for efficient deep-blue OLED with high color purity using purely organic emitter. In this work, we report two phenanthroimidazole-acridine derivatives ( DPM , TDPM ). Twisted combined rigid structures with HLCT properties enable them show decent deep-blue narrow-spectrum emissions of 428 nm and 424 nm, as well as maximum external quantum efficiency (EQE max ) of 4.0% and 2.6%, respectively. Our work provides a molecular design strategy of HLCT materials for efficient deep-blue OLED with nice color purity using purely organic emitter. • Two phenanthroimidazole-acridine derivatives were synthesized for deep-blue OLED. • Non-doped OLEDs based on DPM and TDPM showed decent deep-blue emission with EQE max of 4.0% and 2.6%, respectively. • Extra C-H···π interactions and ordered π-π stacking make OLEDs based TDPM display a smaller efficiency roll-off than that of DPM.