High contrast ratio light-emitting liquid crystal device based on AIEE dyes

Area of Science:

• Materials Science
• Optoelectronics
• Liquid Crystal Displays

Background:

• Liquid crystal devices (LCDs) are widely used in displays.
• Aggregation-induced emission enhancement (AIEE) dyes offer unique photoluminescent properties.
• Optimizing contrast ratio (CR) is crucial for display performance.

Purpose of the Study:

• To fabricate a light-emitting liquid crystal device (LELCD) with high CR.
• To investigate the impact of surface anchoring and cell thickness on CR.
• To explore the use of AIEE dyes in display applications.

Main Methods:

• Fabrication of LELCDs utilizing AIEE dyes and liquid crystals (LCs).
• Employing both horizontal and vertical alignment layers with varied anchoring energies and rubbing strengths.
• Systematic variation of LELCD cell thickness.

Main Results:

• Achieved a CR of approximately 30:1 in a 10 µm thick LELCD.
• Identified weak surface anchoring with polymethyl methacrylate as a horizontal alignment layer as optimal.
• Demonstrated continuous variation of photoluminescent intensity by controlling AIEE dye orientation via electric fields.

Conclusions:

• Weak surface anchoring and optimized cell thickness are key to high CR in AIEE-based LELCDs.
• This study presents the highest CR reported for AIEE-based display devices.
• The developed LELCD technology holds potential for advanced optical devices.