Boosting hole migration through oxygen species–functionalized graphene interlayer for organic-based optoelectronic devices with enhanced efficiency and long-term durability

•Conformal incorporation of O-functionalized graphene (O-Gr) interfacial layer onto PEDOT:PSS.•In DFT calculation, O-containing vacancy in O-Gr efficiently accept holes suppressing recombination.•Incorporated O-Gr films improved interfacial properties and reduced leakage current in the devices.•O-Gr interfacial layer provided a reasonable pathway for hole migration in OPV and OLED.