Simple and Efficient Generation of White Light Emission From Organophosphorus Building Blocks

This paper describes a structure-property study using two dithieno[3,2- b;2',3'-d]phosphole building blocks for the generation of white light emission and the incorporation of these units in a single polystyrene material. The emission of one of the light-emitting organophosphorus build blocks can efficiently be switched from orange to green by simple protonation of the amino functional groups that are part of the pi-conjugated scaffold. The resulting three components (blue, green, and orange) exhibit photophysical properties that allow for an efficient fluorescence resonance energy transfer (FRET) in the mixture/polymer and provide intense white fluorescence upon excitation of the blue component; the fluorescence is close to pure white in solution and similar to the emission of an incandescent light bulb in the thin film. The results nicely illustrate the intriguing features that can be obtained by exclusively using organophosphorus-based organic electronic materials.