Electroluminescent device

This invention relates to electroluminescent devices, especially ones that have a conjugated polymer as a light-emitting layer. An electroluminescent device comprising: a first charge-carrier injecting layer for injecting positive charge carriers and a second charge-carrier injecting layer for injecting negative charge carriers, at least one of the charge-carrier injecting layers being patterned so as to comprise spaced-apart charge-injecting regions; an organic light-emitting layer located between the first and second charge-carrier injecting layers; and an unpatterned conductive polymer layer located between the organic light-emitting layer and the patterned charge-carrier injecting layer, the resistivity of the conductive polymer layer being sufficiently low to allow charge carriers to flow through it from the charge-injecting regions to generate light in the organic light-emitting layer but sufficiently high to resist lateral spreading of charge carriers beyond the charge-injecting regions.