A device configuration for light emission from electroactive polymers
is described. In these light-emitting electrochemical cells, a p-n jun
ction diode is created in situ through simultaneous p-type and n-type
electrochemical doping on opposite sides of a thin film of conjugated
polymer that contains added electrolyte to provide the necessary count
erions for doping. Light-emitting devices based on conjugated polymers
have been fabricated that operate by the proposed electrochemical oxi
dation-reduction mechanism. Blue, green, and orange emission have been
obtained with turn-on voltages close to the band gap of the emissive
material.