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.