Cyclic Emitter with Tetraphenylsilane and Tetraphenylethene Units Exhibiting Tunable Color Emissions

A novel cyclic emitter composed of tetraphenylsilane and tetraphenylethene backbone was successfully synthesized through a convenient homocoupling procedure. The optical and thermal properties of the compound were revealed. Intriguingly, the compound showed different color emissions in solid film, THF solution, and THF/water mixtures. It is assumed that the violet emission was from an isolated component of the emitter, whereas the sky blue and the green emissions were from a crystalline state, and an amorphous state, respectively. The red-shifted emissions were caused by the change of nature of the excitonic coupling.