Tailoring the efficiencies and spectra of white organic light-emitting diodes with the interlayers

Abstract

Charge carriers balance and triplet excitons confinement are two key factors determining the performance of phosphor-based organic light-emitting diodes (OLEDs). The characteristics of white OLED (WOLED) based on complementary blue and yellow phosphors could be easily manipulated by the insertion of an ultrathin interlayer between the two emitters. Both the electrical and the optical characteristics of WOLEDs are significantly dependent on the selection of the interlayers, which tailor charge carrier transportation and energy transfer. The interlayers ease the perplexity of probing the dynamics of charges and excitons. High efficiencies could also be achieved by the effective prevention of the high energy blue triplet excitons from diffusing into the adjacent low triplet states via Dexter transfer. The device with the nominal n-type interlayer and triplets confinement architecture reaches a power efficiency of 40.0 lm/W at ∼100 cd/m2 and a luminance of 1333 cd/m2 at a low voltage of 4.0 V. © 2010 American Chemical Society.