Abstract：We improve the performance of organic light-emitting diodes (OLEDs) with both a MoO3 hole injection layer (HIL) and a MoO3 doped hole transport layer (HTL), and present a systematical and comparative investigation on these devices. Compared with OLEDs with only MoO3 HIL or MoO3 doped HTL, OLEDs with both MoO3 HIL and MoO3 doped HTL show superior performance in driving voltage, power efficiency, and stability. Based on the typical NPB/Alq3 heterojunction structure, OLEDs with both MoO3 HIL and MoO3 doped HTL show a driving voltage of 5.4 V and a power efficiency of 1.41 lm/W for 1000 cd/m2, and a lifetime of around 0.88 h with an initial luminance of 5268 cd/m2 under a constant current of 190 mA/cm2 operation in air without encapsulation. While OLEDs with only MoO3 HIL or MoO3 doped HTL show higher driving voltages of 6.4 V or 5.8 V and lower power efficiencies of 1.20 lm/W or 1.34 lm/W for 1000 cd/m2, and a shorter lifetime of 0.33 or 0.60 h with an initial luminance of around 5122 or 5300 cd/m2 under a constant current of 200 or 216 mA/cm2 operation. Our results demonstrate clearly that using both MoO3 HIL and MoO3 doped HTL is a simple and effective approach to simultaneously improve both the hole injection and transport efficiency, resulting from the lowered energy barrier at the anode interface and the increased hole carrier density in MoO3 doped HTL.
. [J]. 中国物理快报, 2015, 32(07): 77206-077206.
LIU Wei, LIU Guo-Hong, LIU Yong, LI Bao-Jun, ZHOU Xiang. Improvement of Performance of Organic Light-Emitting Diodes with Both a MoO3 Hole Injection Layer and a MoO3 Doped Hole Transport Layer. Chin. Phys. Lett., 2015, 32(07): 77206-077206.
2015, Vol. 32 
