Electrically controllable fluorescence of tristable optical switch based on luminescent molecule-doped cholesteric liquid crystal

• A tristable can be switched among the planar, focal conic and fingerprint states.
• The mixture exhibits stable emission performance.
• The photoluminescence can be controlled using an electric field.
• It has the potential to be used in practical portable information systems.

A tristable and electrically switchable optical switch based on luminescent molecule and cholesteric liquid crystal (CLC) is demonstrated. The CLC can be switched among the planar state, focal conic state and fingerprint state using the electric field. The interaction between the luminescent molecules and indium tin oxide substrate can be modulated by controlling the orientation of the luminescent molecules, which determine the stability of the three states. The optical property and fluorescent intensity of these states depend on the arrangement of liquid crystal molecules and all the three states can exist for several hours at room temperature without any observable change. Such a multi-stable electrical switch is simple to be fabricated, easy to be operated, and has low power consuming. It, therefore, has the potential to be used in practical portable information systems.