Internal color conversion technique

An efficient internal color-conversion technique will only occur if the polymers in the blend are only weakly phase separated. Otherwise, the various polymers in the blend behave similar to independent parallel diodes and hence a strongly voltage-dependent emission color will be observed.131,137... 

Blue Large-Area EL Devices Covered with Filters and Appropriate Dye Layers That Convert the Blue EL Emission into the Required Emission Color. One of the most promising methods for the production of flat color screens is the use of blue PLEDs covered with dye layers to convert the EL emission into the RGB colors and, if necessary, with filters to purify the emission light [171-174] (see Fig. 30.20). In principle, the internal quantum efficiency of this technique for color conversion from blue into any other emission color can approach 100%. 

The analytical methods proposed for acesulfame-K, cyciamate, and saccharin determination in foods, drinks, dietary products, and pharmaceuticals can be grouped into methods for the determination of an individual artificial sweetener [21-27] and multianalyte approaches [28-38], sometimes also including other sweeteners and/or other food additives, such as colorants or preservatives [39-43]. High-performance liquid chromatography (HPLC) is the most frequently used technique for the determination of these sweeteners, and this is selected by international standard methods because of its multianalyte capability, compatibility with the physicochemical properties of sweeteners, high sensitivity, and robustness [44-47]. However, cyciamate requires chemical derivatization to make it detectable by the most commonly employed UV-absorption detector due to a lack of a chromophore, by conversion to dichlorohexylamine for UV detection or to a fluorescence derivative for fluorimetric detection. Another alternative for cyciamate detection is the postcolumn ion-pair extraction where the eluted sweetener is mixed with an appropriate dye (methyl violet or crystal violet), being detected by visible absorption. Furthermore, cyciamate can be detected directly by refractive index [4]. For this, few HPLC methods for the concurrent determination of these sweeteners exist and... 

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