研究了三氧化钼(MoO3)薄层作为有机电致发光器件空穴注入层的器件性能和注入机制。发现1 nm厚度下发光器件性能最佳，器件的最大电流效率比对比发光器件的最大电流效率提高1.6倍。器件的电容曲线表明MoO3薄层能有效提高空穴载流子的注入，多数载流子开始注入的拐点大约降低了9 V。单空穴载流子电流曲线说明MoO3器件的电流注入是空间电荷受限电流注入机制，MoO3使阳极界面处形成欧姆接触，而对比器件的电流注入是陷阱电荷受限电流注入机制。器件的光伏曲线进一步说明器件性能的提高是由于MoO3层能使阳极界面能级分布发生改变，1 nm MoO3厚度下器件的内建电势从对比器件的0.25 V提高到了0.8 V，有效降低了空穴注入势垒，提高了器件性能，但过厚的MoO3层由于增加了器件的串联内阻，会导致器件性能降低。

An efficient hole-injection contact was achieved for organic light-emitting diodes (OLEDs) based on molybdenum oxide (MoO3) as the buffer layer on indium tin oxide. The significant effect of MoO3 is that the devices show low operational voltage and high electroluminescence efficiency in a wide range of MoO3 thickness. The device with a 1 nm-thick MoO3 layer shows the best performance, the current efficiency is enhanced by 1.6 times by comparing with the control device. Capacitance-voltage measurement demonstrated that hole injection is enhanced in low operational voltage through the addition of MoO3. Results of the hole-only devices revealed that ohmic hole injection is formed at ITO/MoO3/NPB interface. Photovoltaic measurements confirmed that the improved hole injection is due to the reduction of barrier height, which is resulted from the addition of transition metal oxide.