Solution-processable hole-generation layer and electron-transporting layer: Towards high-performance, alternating-current-driven, field-induced polymer electroluminescent devices

The effect of solution-processed p-type doping of hole-generation layers (HGLs) and electron-transporting layer (ETLs) are systematically investigated on the performance of solution-processable alternating current (AC) field-induced polymer EL (FIPEL) devices in terms of hole-generation capability of HGLs and electron-transporting characteristics of ETLs. A variety of p-type doping conjugated polymers and a series of solution-processed electron-transporting small molecules are employed. It is found that the free hole density in p-type doping HGLs and electron mobility of solution-processed ETLs are directly related to the device performance, and that the hole-transporting characteristics of ETLs also play an important role since holes need to be injected from electrode through ETLs to refill the depleted HGLs in the positive half of the AC cycle. As a result, the best FIPEL device exhibits exceptional performance: a low turn-on voltage of 12 V, a maximum luminance of 20 500 cd m^-2, a maximum current and power efficiency of 110.7 cd A ^-1 and 29.3 lm W^-1. To the best of the authors' knowledge, this is the highest report to date among FIPEL devices driven by AC voltage. The effect of solution-processed hole-generation layers and electron- transporting layers is systematically investigated on the performance of AC-driven field-induced polymer electroluminescence (FIPEL) devices. A low turn-on voltage of 12 V, a maximum luminance of 20 500 cd m^-2, and a maximum current and power efficiency of 110.7 cd A^-1 and 29.3 lm W^-1 are achieved. This study provides a pathway to high-performance FIPEL device engineering.