Hot wind technique for high-efficiency, fully-solution-processed, multilayer organic light-emitting diodes

Multilayer organic light-emitting diodes (OLEDs) produced by the fully solution-processed method without the dissolution of subsequent layers are necessary to achieve cost-effective high performance devices. Although photo-cross-linkable organic molecules and orthogonal solvents are regarded as promising approaches to avoiding dissolution, fully solution-processed multilayer OLEDs do not demand their use, making it impossible to investigate them and limiting their progress. In this work, a simple technique by means of hot wind that requires only a spin coater and a heat gun and reduces the dissolution problem is developed to produce fully solution-processed multilayer OLEDs. Results show that the average current efficiency is about 18 cd/A and the external quantum efficiency is 6% for devices with areas of 0.4 × 0.4 and 1.4 × 1.4 cm².