High general and special color rendering index white organic light-emitting device with bipolar homojunction emitting layers

High general and special color rendering index (CRI) together with gamut area index (GAI) is demanded for lighting source. In a tolerable Duv, an efficient warm white organic light-emitting device (WOLED) with a high CRI and GAI is developed by using a bipolar homojunction emitting layers, i.e., junction between different emitting layers with the same bipolar host material. At a low drive voltage of 4 V, the WOLED shows a high luminance of 1594 cd/m(2) and a power efficiency of 12.95 lm/W, and, it shows a high general CRI of 82, a special CRI R-9 of 75, an average of R-9 to R-12 of 69 and a GAI of 95. Besides, the WOLED shows relative stable color coordinates due to the elimination of the charges accumulation at interface between different emitting layers. And the current efficiency roll-off of the WOLED is also reduced due to the balance of carrier injection and transport in emitting layers. (C) 2013 Elsevier B.V. All rights reserved.