The manufacture of new full-color displays is one of the main tasks in flat-panel display systems and lighting technology. Different applications place different demands on emitted light: in some cases a white-light source is needed, and in others pure colors are necessary.Thus, white emission should ideally be composed of three (blue, green, and red) or two (blue and yellow) primary colors and cover the whole visible range from 400 to 700 nm, and the emitter should have the ability to emit the primary colors simultaneously with equal intensities to produce white light and the pure colors separately in a tunable way. Considerable interest exists for such color-tunable materials, which can be used to define or modify environments, moods, and brands. Traditional methods of such white light generation typically rely on mixing various primary colors from different emitting materials. An alternative approach for the generation of efficient (white) light sources is to use a single-component emitter, which can have advantages such as greater stability, better reproducibility, no phase separation, and simpler fabrication processes. Although a few materials show white-light emission as a single-emitting component, none has been reported to produce well-separated blue, green, and red emissions beside white light.Since energy transfer typically quenches one or more of the emission pathways and thereby restricts the transitions that define the output spectrum,1'1 the design of color tunable single-component emitters requires readily tailorable different fluorophores and fine-tuning of the energy-transfer processes between the different fluorophores.
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