Disclosed is an OLED device comprising a light-emitting layer (LEL) containing a host and an emitting dopant located between a cathode and an anode wherein the dopant is a naphthacene derivative represented by formula (I): wherein: a) said naphthacene derivative contains at least one fluorine or fluorine containing group; and b) when exactly two fluorine containing groups are present said groups are not located at the 5- and 12-positions or at the 6- and 11-positions.