输运层厚度对双层有机器件复合发光的影响

采用ITO/PVK/Alq/Al双层电致发光(EL)结构,制备了三种载流子输运层厚度分别为30、 60、 120 nm,发光层厚度均为300 nm的有机薄膜EL器件,测试其EL谱及J-V特性曲线.根据有机EL器件中载流子的产生和输运过程导出了载流子复合几率及电子和空穴密度分布表示式,用以解释其发光强度随输运层厚度的变化关系,用一维无序结构载流子随机跃迁模型讨论输运层厚度对器件电流密度及启动电压的影响,探讨了载流子在薄膜中的输运过程,其理论与实验符合得很好.

Influence of Thickness of the Carriers Transport Layer On the EL Properties in Organic Thin Film Electroluminescence

Three organic thin film electroluminescence devices (OELD) with different thickness of carriers transport layer: 30nm, 60nm, 120nm and the same thickness of luminescent layer: 300nm, were prepared. The OELDs were the double layer structure of ITO/PVK/Alq/Al. On the basis of a model for generation transport and recombination of carriers and for carrier arbitrary hopping model in organic light emitting devices, a complete analytic function for exciton fission and recombination and for densities distribution of electron and hole are proposed, comparing and analyzing their EL spectra andJ-Vproperties, it is found that the thickness of carrier transport layer influences the brightness, current density and onset volt of EL devices. The theoretical results are in agreement with the experimental values satisfactorily.