Thick-layer organic light-emitting diodes(OLEDs)comprising a single thick film to simultaneously transport carriers and emit light offer significant advantages in simplifying the fabrication process and enhancing oper...Thick-layer organic light-emitting diodes(OLEDs)comprising a single thick film to simultaneously transport carriers and emit light offer significant advantages in simplifying the fabrication process and enhancing operational stability.However,achieving highly efficient thick-layer non-doped OLEDs requires emitters possessing balanced bipolar carrier transport,strong solid-state emission and high exciton utilization,which impose high requirements on designing luminescent materials.In this work,two representative bipolar aggregation-induced delayed fluorescence(AIDF)emitters are employed to fabricate such thick-layer non-doped devices.Excellent electroluminescence(EL)performances are attained with low turn-on voltages(2.5 V),high external quantum efficiencies(19.8%),and negligible efficiency roll-off at high luminance.Furthermore,the operational lifetime of the thick-layer device increases by more than twofold compared to that of the thin-layer devices.In addition,highefficiency,high-color-purity simplified thick-layer hyperfluorescence OLEDs are also achieved by using their thick neat films as sensitizers for multi-resonance emitters.These results indicate that the bipolar AIDF emitters are promising candidates for constructing simple thick-layer OLEDs,which provides a feasible strategy for developing highly efficient and stable OLEDs.展开更多
文摘Thick-layer organic light-emitting diodes(OLEDs)comprising a single thick film to simultaneously transport carriers and emit light offer significant advantages in simplifying the fabrication process and enhancing operational stability.However,achieving highly efficient thick-layer non-doped OLEDs requires emitters possessing balanced bipolar carrier transport,strong solid-state emission and high exciton utilization,which impose high requirements on designing luminescent materials.In this work,two representative bipolar aggregation-induced delayed fluorescence(AIDF)emitters are employed to fabricate such thick-layer non-doped devices.Excellent electroluminescence(EL)performances are attained with low turn-on voltages(2.5 V),high external quantum efficiencies(19.8%),and negligible efficiency roll-off at high luminance.Furthermore,the operational lifetime of the thick-layer device increases by more than twofold compared to that of the thin-layer devices.In addition,highefficiency,high-color-purity simplified thick-layer hyperfluorescence OLEDs are also achieved by using their thick neat films as sensitizers for multi-resonance emitters.These results indicate that the bipolar AIDF emitters are promising candidates for constructing simple thick-layer OLEDs,which provides a feasible strategy for developing highly efficient and stable OLEDs.
