Performance enhancement of blue quantum dot light-emitting diodes via LiCl doped PEDOT∶PSS
Full solution-processed quantum dot light-emitting diodes(QLEDs)typically suffer from the problem of electron-hole injection imbalance,which severely limits the performance improvement of blue QLEDs devices.The effects of metal halide(LiCl)doping on the morphology,conductivity and light transmittance of poly(ethylenedioxythiophene)∶polystyrene sulfonate(PEDOT∶PSS)films and the device performance of the prepared QLEDs were investigated.The experimental results show that the best effect on the enhancement of blue QLED device performance is achieved when the doping concentration of LiCl is 2%(mass fraction),which is mainly attributed to the enhancement of conductivity and transmittance of LiCl-doped PEDOT∶PSS films as well as the improvement of hole injection efficiency in the devices.Compared with the undoped PEDOT∶PSS-based QLED devices,the maximum brightness,current efficiency,power efficiency and external quantum efficiency of the LiCl-doped blue QLED devices are increased to 7 451 cd·m-2,1.38 cd·A-1,0.89 lm·W-1 and 3.51%from 5 083 cd·m-2,0.91 cd·A-1,0.59 lm·W-1 and 2.31%,respectively.The results show that the use of LiCl-doped PEDOT∶PSS hole injection layer is an effective strategy to improve the performance of blue QLEDs.
blue quantum-dot light-emitting diodesPEDOT∶PSSLiCl-dopinghole injection layerhole injection
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