Highly efficient organic light-emitting diode is fabricated with a novel double hole injection layer consisting of MeO-TPD/CuPc. We observe that the insertion of such a double hole injection layer leads to a striking enhancement in the electrical property: higher luminance, power efficiency and lower driving voltage. It has the configuration of ITO/MeO-TPD (15 nm)/CuPc(15 nm)/NPB(15 nm)/Alq3 (50 nm)/LiF(1 nm)/Al(120 nm). Its turn-on voltage is 3.2 V, which is 2, 0.3 and 0.1 V lower than those of the device without hole injection layer (device A) and the devices using MeO-TPD (device B), CuPc (device C) as hole injection layer, respctively. The highest luminance of the novel device reaches 23893 cd/m2 at a drving voltage of 10 V. The maximum power efficiency of the novel decive is 1.91 lm/W, which is 43%(1.34 lm/W), 22%(1.57 lm/W) and 7%(1.79 lm/W) higher than those of devices A, B and C, respectively. The improvement is ascribed to its high hole injection and transport ability. The results are verified by using the J-V curves of“hole-only”devices.% 采用新型双空穴注入层N, N, N′, N′-tetrakis(4-Methoxy-phenyl)benzidine/Copper phthalocyanine(MeO-TPD/CuPc)及器件结构： ITO/MeO-TPD(15 nm)/CuPc(15 nm)/ N, N′-Bis(naphthalen-1-yl)-N, N′-bis(phenyl)benzidine (NPB,15 nm)/8-hydroxyquinoline (Alq3,50 nm)/LiF(1 nm)/Al(120 nm),研制出高效有机发光二极管(器件D),与其他器件(器件A,没有空穴注入层的器件；器件B, MeO-TPD单空穴注入层；器件C, CuPc单空穴注入层)相比,其性能得到明显改善.器件D的起亮电压降至3.2 V,比器件A, B, C的起亮电压分别降低了2,0.3,0.1 V.器件D在10 V时,其最大亮度为23893 cd/m2,最大功率效率为1.91 lm/W,与器件A, B, C的最大功率效率相比,分别提高了43%(1.34 lm/W),22%(1.57 lm/W),7%(1.79 lm/W).性能改善的主要原因是由于空穴注入和传输性能得到了改善,通过单空穴型器件的J-V 曲线对这一现象进行了分析.
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