Efficient solution-processed OLEDs featuring deep-blue triplet-triplet annihilation emitter based on pyrene derivative

Achieving high efficiency deep-blue organic light-emitting diodes (OLEDs) with a CIEy < 0.08 is still terribly urgent yet challenge. Herein, we designed and synthesized a novel blue triplet-triplet annihilation (TTA) emitter with a fan-shape torsional molecular structure, namely TbuPyB, which is based on benzene as core and three tert- butylpyrene as arm. The photophysical, electrochemical and electroluminescent performances of TbuPyB were systematically investigated. Intense deep-blue/blue emissions peaked at 413 and 472 nm are observed in the 7 wt % doped 1,3-bis(N-carbazolyl)benzene (mCP) thin film and neat film, accompanied by absolute photo-luminescence (PL) quantum yield (PLQY) of 66.3% and 74.8%, respectively. Contributed by the TTA process, the solution-processed non-doped device exhibits blue emission peak at 470 nm with an impressive EQE of 10.65% and a CIE coordinates of (0.15, 0.20) at the voltage of 7.8 V. In contrary, at the 7 wt% dopant concentration, an outstandingly 57 nm violet-shifted deep-blue emission at 413 nm with an EQE of 6.87% and a CIE coordinates of (0.15, 0.06) was achieved in the doped device. These results schedule a novel avenue for designing highly efficient deep-blue emitter in the solution processable OLEDs.