Double Boron–Oxygen-Fused Polycyclic Aromatic Hydrocarbons: Skeletal Editing and Applications in Organic Optoelectronic Materials

Abstract

We developed an efficient one-pot strategy for the facile synthesis of novel double boron–oxygen-fused polycyclic aromatic hydrocarbons (dBO-PAHs) with high regioselectivity and efficient skeletal editing. The BO-fused rings exhibit low aromaticity, endowing the dBO-PAHs with high chemical and thermal stabilities. The incorporation of the B–O units enables the dBO-PAHs to show single-component, low-temperature ultralong afterglow of up to 20 s after UV excitation. Moreover, the dBO-PAHs can also serve as ideal n-type host materials for high-brightness and high-efficiency deep-blue organic light-emitting diodes (OLEDs); compared to single host, BO1b:mCBP co-hosts-based deep-blue OLEDs exhibited dramatically brightness and efficiency enhancements with significantly reduced efficiency roll-offs; device 7 using PtON1 as emitter achieved a maximum brightness (Lmax) of 15722 cd/m2 with a peak EQE of 27.1%, which represented the record-high Lmax among Pt(II)-based deep-blue OLEDs with CIEy < 0.20; device 9 employing PtON-TBBI as emitter demonstrated a 4.6-fold Lmax enhancement with a high color-purity (CIEy = 0.104), and also achieved a record-high EQE (28.0%) among Pt(II)-based deep-blue OLEDs. This work demonstrates the great potential of the dBO-PAHs as ultralong afterglow and novel n-type host materials in optoelectronic applications.