The present invention is directed to an organic light emitting diode (100) comprising: at least one anode electrode (120); at least one emission layer (150), wherein the emission layer comprises at least one emitter dopant that emits visible light at operation of the OLED (100); an electron transport layer stack (160) of at least two electron transport layers (161/162), and wherein a) the first electron transport layer (161) comprises i) a first organic aromatic matrix compound having a MW of about ≥400 to about ≤1000 and a dipole moment of about ≥0 Debye and about ≤2.5 Debye, wherein the first electron transport layer (161) is free of a polar organic aromatic phosphine compound; and b) the second electron transport layer (162) comprises two organic aromatic matrix compounds, which are a mixture of: i) the first organic aromatic matrix compound; and ii) a polar organic aromatic phosphine compound having a MW of about ≥400 to about ≤1000, and a dipole moment of about >2.5 Debye and about ≤10 Debye; and at least one cathode electrode layer (190); wherein the electron transport layer stack (160) is arranged between the emission layer (150) and the cathode electrode layer (190), the first electron transport layer (161) is in direct contact with the second electron transport layer (162), and wherein the first electron transport layer (161) is arranged nearer to the emission layer (150) and the second electron transport layer (162) is arranged nearer to the cathode electrode layer (190).