A high-κ homogeneous ink for printable electroluminescent devices

Area of Science:

• Materials Science
• Optoelectronics
• Polymer Chemistry

Background:

• Flexible alternating-current electroluminescent (ACEL) devices offer unique applications but face challenges with low driving voltage, transparency, and pattern clarity due to heterogeneous fillers.
• Existing high-permittivity fillers (e.g., BaTiO₃, liquid metals) compromise optical properties and pattern definition in ACEL devices.

Purpose of the Study:

• To develop a printable, transparent, high-dielectric ink for ACEL devices that overcomes limitations of previous filler materials.
• To enable efficient, low-voltage operation and scalable fabrication of high-quality, patterned ACEL devices.

Main Methods:

• Incorporation of small high-dielectric molecules into a polymer matrix to create a novel ink formulation.
• Utilized screen printing and one-step photopolymerization for fabricating patterned ACEL devices.
• Characterized the ink's dielectric properties (constant up to 25) and optical transparency (up to 90%).

Main Results:

• Achieved efficient light emission at a low driving voltage of approximately 0.33 V µm⁻¹, among the lowest reported values.
• Demonstrated excellent printability for scalable, cost-effective patterning of ACEL devices.
• Fabricated high-quality patterned ACEL devices with high transparency and clarity.

Conclusions:

• The developed printable, transparent high-dielectric ink significantly advances ACEL device technology.
• Enables low-voltage, efficient, and scalable fabrication of flexible electronic devices.
• Facilitates potential for chip- and battery-free operation through wireless power harvesting.