Polyphenylbenzene as a Platform for Deep-Blue OLEDs: Aggregation Enhanced Emission and High External Quantum Efficiency of 3.98%

Great efforts have been devoted to seek novel approaches for the construction of efficient deep-blue fluorescent materials, one of the most important prerequisites for the commercialization of OLEDs. Here, we report a new way to utilize polyphenylbenzene as a platform to yield a series of efficient deep-blue emitters. Nondoped multilayer electroluminescence (EL) devices using these new luminogens as emitting layers are fabricated. Maximum current efficiency (CE) of 2.0 cd A–1 is achieved and the Commission Internationale de l’Eclairage (CIE) coordinates can stay at (0.15, 0.08), close to the saturated deep-blue (0.14, 0.08). Through rational design of the device structure, blue-violet emission with the CIE coordinates of (0.15, 0.06) can be realized. Furthermore, 10-based doped devices show deep-blue emission with improved CE as high as 4.51 cd A–1, and the external quantum efficiency (EQE) of 3.98%, which are among the best EL performance for deep-blue emission.