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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1nm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9V。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,1nmMoO3厚度下器件的内建电势从对比器件的0.25V提高到了0.8V,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。
The device performance and implantation mechanism of molybdenum trioxide (MoO3) thin film as a hole injection layer in organic electroluminescent devices were studied. It is found that the best performance of the light-emitting device at a thickness of 1 nm shows that the maximum current efficiency of the device is 1.6 times higher than that of the comparative light-emitting device. The capacitance curve of the device shows that the MoO3 thin film can effectively increase the hole carrier injection, and the inflection point of majority carrier injection start is reduced by about 9V. The single-hole carrier current curve shows that the current injection into the MoO3 device is a space-charge-limited current injection mechanism, with MoO3 forming an ohmic contact at the anode interface, whereas the current injection of the comparative device is a trapped charge-limited current injection mechanism. The photovoltaic curve of the device further shows that the improvement of the device performance is due to the change of the energy level distribution of the anode interface caused by the MoO3 layer. The built-in potential of the device with the thickness of 1nmMoO3 increases from 0.25V to 0.8V of the comparative device, effectively reducing the hole injection potential The barrier improves the performance of the device, however, the thick MoO3 layer will lead to the degradation of the device performance due to the increased internal resistance of the device.