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Journal article
Organic light-emitting devices with a hole-blocking layer inserted between the hole-injection layer and hole-transporting layer
Yoga Divayana Chen Baijun Sun Xiaowei Sarma K. S.
Volume : 88 Nomor : 8 Published : 2006, February
Applied Physics Letters
Abstrak
A hole-blocking layer (HBL), 2,9-dimethyl-4, 7-diphenylphenanthroline (BCP), was incorporated between the hole-transporting layer (HTL) and hole-injection layer for a tris-(8-hydroxyqunoline) aluminum-based organic light-emitting device. Such a structure helps to reduce the hole-leakage to the cathode resulting in improved current efficiency. Optimum BCP thickness of around 3 nm was observed to produce a current efficiency of 3.25 cd/A, which corresponds to a 30% improvement compared to that of the standard device without BCP (2.5 cd/A). Low operating voltage was also achieved by minimizing the thickness of the HTL. Both operating voltage and efficiency can be tuned by varying the thickness of HTL and HBL, respectively.