RESUMO
We realized an efficient spectra-stable tandem white organic light-emitting device (WOLED) with pleasurable warm white emission and an extremely high color-rendering index (CRI) simultaneously by connecting a fluorescent blue unit and a phosphorescent dual-color unit via an easy-fabrication charge generation unit (CGU). Over a wide range of driving current density, the tandem warm white OLED exhibited general CRI (Ra) value exceeding 85 and special CRI (R9) value close to 57. In addition, Duvs are within the tolerance for CRI measurements, ensuring validity and logicality of the calculated results concerning Ra and R9. The obtained tandem OLED showed the maximum efficiencies of 38 cd/A and 22.9 lm/W, and still maintained high efficiencies of 35.5 cd/A and 17.2 lm/W at the luminance of 1000 cd/m2. Moreover, we studied the origins of both extreme color stability in dual-color OLED and extremely efficient electron injection within the CGU. To the best of our knowledge, this is the first report regarding quantitative values of both R9 and the Duv for a high-Ra tandem WOLED.