The effects of solvent vapor annealing on the performance of blue polymer light-emitting diodes

In this manuscript, we reported the effects of solvent vapor annealing on performances of blue polymer light-emitting diodes, where the blue light-emitting poly(dibenzothiophene-S,S-dioxide-co-dioctyl-2,7-fluorene) that comprising dibenzothiophene-S,S-dioxide with molar ratio of 10% was used as the emissive layer, and toluene or chloroform was use as the annealing solvents. It was noted that the performances of PLED in terms of both luminous efficiency and brightness were obviously enhanced by solvent vapor annealing treatment, which can be correlated to the improved film morphology. The formation of β-phase lead to more balanced electron and hole flux as evaluated by single carrier devices. The best device performance with luminous efficiency of 4.8 cd/A was realized, which increased about 70% relative to that of 2.77 cd/A for the pristine device. These observations demonstrated that the solvent vapor annealing approach can be an effective strategy to improve performances of polymer light-emitting diodes.