Indenocarbazole and benzofurocarbazole-based bipolar host materials for high-performance red and green Phosphorescent Organic Light-Emitting Diodes

In this research, two innovative bipolar host materials, DMID-BP and BFCz- BP, were strategically designed and synthesized, marking the first application of these materials in red and green phosphorescent organic light-emitting diodes. Both compounds exhibit remarkable bipolar carrier transport properties, well aligned HOMO and LUMO levels, and exceptional thermal stability, with T g value of 185 °C and 171 °C, respectively. The red and green Phosphorescent Organic Light-Emitting Diodes (PhOLEDs) fabricated with these two materials demonstrate high light-emitt ing efficiency along with low efficiency roll-off. Notably, R1 device, utilizing DMID -BP as the host material, achieves an impressive maximum external quantum efficiency (EQE max ) of 23.68 %, significantly surpassing most conventional host materials reported to date. Additionally, the R2 device, based on BFCz -BP, also attains a high EQE max of 20.26 %. Consequently, all the results underscore the significant potential of these two host materials for applications in both red and green PhOLEDs. • Two novel bipolar host materials, DMID-BP and BFCz-BP, were strategically designed and synthesized for red and green PhOLEDs. • The impact of DMID and BFCz units on thermal stability, energy levels, and charge transport balance was systematically evaluated. • High external quantum efficiencies of 23.68% (DMID-BP) and 20.26% (BFCz-BP) were achieved in red PhOLEDs, with minimal roll-off efficiency.