Sunlight like white organic light emitting diodes with inorganic/organic nanolaminate distributed Bragg reflector (DBR) anode microcavity by using atomic layer deposition
Abstract White organic light emitting diodes (WOLED) with inorganic/organic/hybrid nanolaminate distributed Bragg reflector (DBR) prepared by atomic layer deposition (ALD) has been firstly developed, and the improved structural, optical, and electrical properties have been observed. The functional layer consists of periodically alternating layers of ZrO2/Zircone (zirconium alkoxides with carbon containing backbones) films fabricated using ALD. By well adjusting the thickness and emissive dyes of the emission layer, three white light diodes were realized based on three cavity modes with different resonance wavelength and intensity. The narrowed lectroluminescent (EL) spectra from the microcavity organic light emitting diodes (MOLEDs) are of high purity, and the off resonant optical mode is highly suppressed due to the excellent optical properties of the DBR layers with high reflectivity in a wide stop band range. The CIE chromaticity coordinates of devices are tuned from (0.33, 0.34) (0.43, 0.40) to (0.57, 0.40) which are all on the planckian locus, and the color temperature is adjusted from 5783 K, 3842 K to 2245 K. This work exhibits a simple and novel approach to achieve a sunlight like WOLED by constructing the inorganic/organic nanolaminate DBR using ALD, which will be very important for healthy display and lighting.