Methods and devices utilizing soluble conjugated polymers

A method of forming adjacent layers of conjugated polymers on a substrate, comprising:

• providing a first solution comprising a first conjugated polymer and a polar solvent, wherein the first conjugated polymer comprises polar groups as pendant solubilizing groups covalently bonded to the conjugated polymer;
• providing a second solution comprising a second conjugated polymer and a second solvent;
• depositing a first layer of said first solution onto the substrate and removing the polar solvent from the first layer;
• depositing a second layer of said second solution onto said first layer and removing the second solvent from the second layer;
• wherein the polymer deposited in the first layer does not dissolve in the second solvent,
• wherein the first conjugated polymer has a highest occupied molecular orbital (HOMO) at an energy within the valence band of the second conjugated polymer whereby said energy allows said layers to function in an electronic device.