| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1327987 | Journal of Organometallic Chemistry | 2008 | 10 Pages |
A cyclometalated iridium(III) complex containing 2-(9,9-diethylfluoren-2-yl)pyridine [Ir(Flpy)3] was prepared and used in the fabrication of both yellow and white organic light-emitting diodes (OLEDs). A hole-blocking material has been used as a hole barrier layer in-between different emission layers, helping the formation of the hole limitation region. With the proper position of a hole barrier layer and the construction of a four-emission-layer structure involving the use of [Ir(Flpy)3], the resulting WOLED shows sound device performance as well as very stable color even at high luminances. Such WOLEDs have been demonstrated to reveal superior white light color stability/efficiency trade-off optimization. The Commission Internationale de L’Eclairage (CIE) coordinate differences Δx and Δy are confined to ±0.015 when the luminance increases from 13 to 14806 cd/m2. The color rendering index (CRI) of the device is also very good, which varies only from 86 to 87 by changing from the normal direction to 80° off-normal at 12 V. The peak electrophosphorescence efficiency can reach as high as 24.6 cd/A at 168 cd/m2and it can still be kept at 17.2 cd/A at 10834 cd/m2. Such outstanding performance renders this all-phosphor WOLED very attractive as a white light source for illumination applications, which typically demand high efficiency, high CRI, and stable color in high brightness work conditions.
Graphical abstractA white organic light-emitting diode (WOLED) consisting of multiple-emissive-layer structure was realized by combining an efficient yellow-emitting iridium complex of fluorenylpyridine with red, green and blue phosphors for color mixing. The device shows an excellent color stability with high and stable color rendering index. The peak WOLED efficiencies can reach 13.0% ph/el, 24.6 cd/A and 12.4 lm/W, respectively.Figure optionsDownload full-size imageDownload as PowerPoint slide
