Performance improvement of inverted polymer solar cells thermally evaporating nickel oxide as an anode buffer layer

► NiO thin film can module the Schottky barrier and form an ohmic contact at the organic/metal interface. ► PCE increases by fivefold with 2 nm NiO compared to the control cell without NiO. ► Tendency of EQE with different thicknesses of NiO is consistent with J-V characteristics.