Production method for organic electroluminescent element
View Patent ↗Disclosed is a production method for an organic electroluminescent element that is provided with a substrate, an organic laminate with an organic light emitting layer that was formed by a method involving a wet process, and a pair of electrodes, wherein the method produces an organic electroluminescent element with high luminous efficiency, low driving voltage, and a minimal rise in voltage when continuously driven, by applying the coating liquid for said organic light emitting layer, and thereafter, in a drying process, heating the substrate while applying tension in a manner such that a stress that is less than the yield stress is applied to the substrate.
1. A producing method of an organic electroluminescence element having a substrate, an organic laminated body containing an organic light emitting layer which is produced with a wet process, and a pair of electrodes, the producing method comprising the steps of:
applying a coating solution of the organic light emitting layer to the substrate, thereafter
drying the organic light emitting layer by heating the substrate while applying a tension to the substrate in a manner that a stress of less than a yield stress of the substrate is given to the substrate,
wherein a film density (A) of the organic light emitting layer and a film density (B) of a layer produced by vapor depositing the same material used for the organic light emitting layer satisfy the following scheme,
−0.02 g/cm3≦( B )−( A )≦0.15 g/cm3.
2. The producing method of an organic electroluminescence element of claim 1 ,
wherein the drying step contains a constant rate drying step and a decreasing rate drying step, the tension is not given to the substrate during the constant rate drying step, and the tension is given to the substrate during the decreasing rate drying step in a manner that a stress of less than a yield stress of the substrate is given to the substrate.
3. The producing method of an organic electroluminescence element of claim 1 ,
wherein the tension to the substrate is applied in two axis directions.
4. The producing method of an organic electroluminescence element of claim 1 ,
wherein the applied tension is in the range of 0.01 N/m to 50 N/m.
5. The producing method of an organic electroluminescence element of claim 1 ,
wherein the stress is 0.33 to 165 kPa.
6. The producing method of an organic electroluminescence element of claim 1 ,
wherein a film density (A) of the organic light emitting layer and a film density (B) of a layer produced by vapor depositing the same material used for the organic light emitting layer satisfy the following scheme,
−0.02 g/cm3≦( B )−( A )≦0.06 g/cm3.
7. The producing method of an organic electroluminescence element of claim 1 ,
wherein the substrate contains a material which exhibits flexibility.