There are no particular restrictions on the heating temperature and duration after coating so long as the polymerization reaction proceeds, but the heating temperature is generally from 100 to 200° C., and preferably from 120 to 160° C. The heating time is generally from 1 to 120 minutes, preferably from 1 to 60 minutes, and more preferably from 1 to 30 minutes.
Further examples include a polymerization reaction under UV irradiation, a polymerization reaction with a platinum catalyst, and a polymerization reaction with an iron catalyst such as iron chloride. These polymerization methods may be used in combination with a polymerization method involving heating.
(Light-Emitting Layer)
<Light-Emitting Material>
The light-emitting material contained by the light-emitting layer in the present invention is oriented in the horizontal direction with the substrate in the light-emitting layer. In the present application, [the phrase] “the light-emitting material is oriented in the horizontal direction with the substrate” refers to a state in which the long-axis direction of the light-emitting material and the direction of the horizontal plane of the substrate substantially coincide, or in the case of a planar light-emitting material, a state in which the plane of the light-emitting material and the direction of the horizontal plane of the substrate substantially coincide. Whether the light-emitting material is oriented in the horizontal direction with the substrate can be confirmed by a method such as the deflection measurement of photoluminescence discussed, for example, in non-patent document titled ATR-IR Deflection Measurement (Applied Physics Letters, Vol. 96, 073302).