Effects of carrier barrier on voltage controllable color tunable OLEDs

Abstract

The effects of the carrier blocking layer on the emission color of the color tunable organic light emitting devices (OLEDs) have been investigated. Color tuning is controlled by the applied voltage. Both the experimental and theoretical results show that inserting a hole blocking layer between two adjacent emission layers will make the color tunable region move toward the wide bandgap emission layer of blue color in our case. By replacing the hole blocking layer with an electron blocking layer, the color tunable region will shift toward the small bandgap emission layer of red. Besides shifting the tunable region toward the pure spectral color, the introduction of the carrier blocking layer can extend the color tunable range. © 2007 Springer-Verlag.