A method is taught for forming a layer of polymeric electroluminescent material having a controlled thickness and surface uniformity. A polymeric electroluminescent material is delivered to a vessel. A fluid to the vessel is also delivered to the vessel. The fluid and the polymeric electroluminescent material in the vessel are compressed and heated to form a thermodynamically stable or metastable mixture. The thermodynamically stable or metastable mixture is sprayed at a surface, the fluid vaporizing during spraying with the the polymeric electroluminescent material being deposited as a light emitting layer on the surface.