a method of forming an electroluminescent device comprising the steps of : providing a substrate comprising a first electrode for injecting charge carriers of a first type ; forming an electroluminescent layer having a surface by depositing onto the substrate a composition comprising a host material and a light - emitting dopant monomer of formula : a - c — n wherein x represents a polymerisable group ; a represents a light - emitting group ; c represents a bond or a spacer group and n is an integer ; rendering at least some of the electroluminescent layer insoluble in a solvent by polymerising the monomer of formula ; exposing the electroluminescent layer to the solvent ; and depositing a second electrode capable of injecting charge carriers of a second type over the electroluminescent layer .