顶发射白光OLED器件制备及其色坐标漂移机制研究

采用了高反射率金属 Al 和电化学性能稳定的金属 Mo,在硅基底上制备了多层结构的 Al/Mo/MoO3阳极,并研究了不同 MoO3厚度下多层阳极的反射率。在此基础上,通过发光层共掺杂制备了顶部发光OLED器件,并对器件发光机制进行了系统研究和分析。实验结果表明：采用发光层共掺杂制备的顶部发光OLED器件的色坐标,随电流密度或电压的增加而发生漂移；OLED器件色坐标漂移的原因是三基色发光强度随电流密度的增加,逐渐偏离了形成白光(0.33,0.33)所需三基色强度比例值,导致了OLED器件的色坐标发生了漂移,其机制是发光层中主-客之间能量转移和陷阱共同作用的结果。进一步研究发现,在不同电压下,红光发光强度随驱动电压(或电流密度)增大而线性地减小。

Research on the Preparation and Chromaticity Coordinates Shift Mechanism of Organic White Light Top-Emitting Devices

The top emission organic light-emitting devices were fabricated on the multi-layers metal anode with co-doping method in single host system.In experiment,the multilayer Al/Mo/MoO3 anode on silicon are de-posited,systematically analyzed the effect MoO3 thickness on the reflectance and found the mechanism of the MoO3 thickness variation to the reflectivity of Al/Mo/MoO3 on silicon.Experimental results showed that the luminous intensity of blue,green and red appear to change according to the current density increase,and com-pared with the red intensity,the luminous intensity of blue and green gradually increased.The emission in this host-guest co-doping system is considered to usually involve two emission mechanisms,energy transfer and carrier trapping,and the energy transfer and carrier trapping between the host-guest should be responsible for chromaticity coordinates shift of organic white emitting light devices.In addition,through further study,it is proved the electroluminescence intensity of dopant linearly decrease with the driving voltage applied to the de-vice by theoretical and experimental results.