Silver-doped nickel oxide as an efficient hole-transport layer in polymer light-emitting diodes

In this study, silver-doped nickel oxide (NiO:Ag) was successfully synthesized by a sol-gel method and spin-coated on indium titanium oxide (ITO) as a hole-transport layer for polymer light-emitting diodes (PLED). After the calcination of the NiO:Ag/ITO substrate at 300°C for 1 h, stable conductive regions and the mean work-function on the NiO:Ag/ITO surface reached 89.43% and 5.53 eV, respectively, which were greater than those on a conventional poly [3,4-ethylenedioxythiophene] polystyrene sulfonate (PEDOT:PSS)/ITO surface. When NiO:Ag (300°C)/ITO was used as an anode window substrate for PLEDs, the enhancement factor for the average current efficiency in the current-density range of 20-50 mA/cm² and electroluminescence intensity at an applied bias of 8.0 V were 4.60 and 2.55 times, respectively, in comparison with those of PLED based on a conventional PEDOT:PSS/ITO anode. HIGHLIGHTS: NiO:Ag is synthesized by a sol-gel method and spin-coated on ITO as a HTL for PLED. NiO:Ag/ITO calcined at 300°C for 1 h has the best microscopic electrical properties. The performance for proposed PLED is much better than that for typical PLED.