A Host Material for Deep-Blue Electrophosphorescence Based on a Cuprous Metal–Organic Framework

Although metal–organic frameworks (MOFs) have promising applications in various fields, efforts to utilize MOFs as emissive layers in electroluminescent devices have not progressed well due to their intrinsic nature. Fortunately, by using fluorene derivatives and cuprous ions, a novel MOF (Cu-P6) has been synthesized for blue electrophosphorescence. The topological structure of Cu-P6 displays a 3-connected uninodal net with a cross-stacking pattern. Such a structure allowed phosphorescent Cu-P6 to exhibit a good heat resistance and luminous efficiency (Φ = 0.62) at crystalline state. By containing both donor and acceptor in the structure, Cu-P6 possesses a balanced electron and hole mobility. Especially, electrical-driven deep-blue emission of a MOF was reported for the first time. Overall, this work may open new perspectives on developing highly efficient electrophosphorescent devices based on MOFs. The utilization of earth-abundant cuprous ions is another attractive feature of Cu-P6.