A sterically shielded design on anthracene-based emitters for efficient deep-blue organic light-emitting diodes

Two new anthracene derivatives are designed with a sterically shielded strategy for deep-blue electroluminescence applications. The naphthyl groups of the widely used blue emitter 9,10-di-(2-naphthyl)anthracene (ADN) were modified with four peripheral phenyl groups (PPGs) to enhance intermolecular spacing in solid-state thin film for suppressing electronic coupling. Influence of the PPGs decoration on photoluminescence and electroluminescence are investigated to reveal the structure-property relationship. A nondoped organic light-emitting diode with the new emitter 9-(naphthalen-2-yl)-10-(5,6,7,8-tetraphenylnaphthalen-2-yl)anthracene (M1) exhibits excellent performance with a maximum external quantum efficiency of 5.05% and deep-blue color index of (0.15, 0.09). Although the use of bulky peripheral substituents does improve device performance, it should be paid attention to the non-conductive effect induced by the larger molecular spacing in the design of deep-blue electroluminescence materials. This work provides a promising molecular design for deep-blue electroluminescence materials.