The cathode interlayer is of crucial importance for efficient electron injection in inverted polymer light-emitting diodes (PLEDs) to realize high electroluminescence efficiency. Here, a novel photoconductive cathode interlayer based on organic dye-doped ZnO (ZnO:PBI-H) is applied as the cathode buffer layer in PLEDs, and dramatically enhanced device performance is obtained. The photodoping of ZnO may greatly promote the electron injection ability under the device working conditions, which increases the electron–hole recombination efficiency when using P-PPV as the light-emitting material. Thanks to the decreased energy barrier between the cathode interlayer and the light-emitting layer, the turn-on voltage of the PLEDs is obviously reduced when using the photoconductive cathode interlayer. Our results indicate that photodoping of the cathode interlayer is a promising strategy to increase the interlayer performance in light-emitting diodes.

中文翻译：

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反向聚合物发光二极管中增强电子注入的光电导阴极中间层

阴极夹层对于在反向聚合物发光二极管（PLED）中实现高效电子注入以实现高电致发光效率至关重要。在此，将基于有机染料掺杂的ZnO（ZnO：PBI-H）的新型光电导阴极中间层用作PLED中的阴极缓冲层，从而显着提高了器件性能。ZnO的光掺杂可以大大提高器件工作条件下的电子注入能力，当使用P-PPV作为发光材料时，可以提高电子-空穴复合效率。由于阴极夹层和发光层之间的能量势垒减小，因此当使用光电导阴极夹层时，PLED的开启电压明显降低。