Effect of graphene oxide doped pedot:Pss as a hole injection layer on the luminescence performance of organic light-emitting diodes

Abstract

We prepared organic light-emitting diodes (OLED) using graphene oxide (GO) doped poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as a hole injection layer (HIL). The PEDOT:PSS: GO HIL layer was prepared by mixing GO into a PEDOT:PSS aqueous solution and spin-coating onto indiumtin oxide (ITO). The luminance of the ITO/PEDOT:PSS:GO (w)/NPB/Alq3/LiF/Al devices were investigated. High luminance and luminous efficiency at a low turn-on voltage were observed when using PEDOT:PSS:GO as the HIL layer in OLEDs. This can be attributed to its enhanced hole injection ability, conductivity and transparency compared to a PEDOT:PSS HIL layer based OLED. The optimized OLED containing PEDOT:PSS:GO (0.8%, mass fraction) composite HIL layer shows a transmission value of 96.8%, maximum luminance and luminous efficiency of 17939 cd∙m-2 (at 7.5 V) and 3.74 cd∙A-1 (at 5.5 V), respectively. These were 46.6% and 67.6% higher, respectively, compared to the reference OLED containing a PEDOT:PSS HIL layer.