Increased efficiency in vertically segregated thin-film conjugated polymer blends for light-emitting diodes

The effect of film morphology on the performance of conjugated polymer-blend light-emitting diodes (LEDs) has been investigated. Vertically segregated structures have been fabricated by varying the spinning conditions and solvents used so that phase separation normal to the substrate is induced. External quantum efficiencies show that LEDs made with vertically segregated structures are between 25% and 100% more efficient than laterally segregated LEDs, depending on the scale of lateral phase separation.