Effects of transparent MPTMS/Ag/MoO₃ structure as anode on the performance of green organic light-emitting diodes

Abstract

A transparent 3-mercaptopropyl trimethoxysilane (MPTMS)/Ag/MoO₃ composite anode is introduced to fabricate green organic light-emitting diodes (OLEDs). Effects of the composite anode on brightness and operating voltage of OLEDs are researched. By optimizing the thickness of each layer of the MPTMS/Ag/MoO₃ structure, the transmittance of MPTMS/Ag (8 nm)/MoO₃ (30 nm) reaches over 75% at about 520 nm. The sheet resistance is 3.78 Ω/□, corresponding to this MPTMS/Ag (8 nm)/MoO₃ (30 nm) structure. For the OLEDs with the optimized anode, the maximum electroluminescence (EL) current efficiency reaches 4.5 cd/A, and the maximum brightness is 37 036 cd/m². Moreover, the OLEDs with the optimized anode exhibit a very low operating voltage (2.6 V) for obtaining brightness of 100 cd/m². We consider that the improved device performance is mainly attributed to the enhanced hole injection resulting from the reduced hole injection barrier height. Our results indicate that employing the MPTMS/Ag/MoO₃ as a composite anode can be a simple and promising technique in the fabrication of low-operating voltage and high-brightness OLEDs.

Keywords

Sheet Resistance / Hole Injection / Apply Physic Letter / Atomic Force Micro / Composite Anode

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This work has been supported by the National Natural Science Foundation of China (No.21174036), the National High Technology Research and Development Program of China (863 Program) (No.2012AA011901), and the National Basic Research Program of China (973 Program) (No.2012CB723406).