Two-Color Pixel Patterning for High-Resolution Organic Light-Emitting Displays Using Photolithography

Area of Science:

• Materials Science
• Organic Electronics
• Display Technology

Background:

• The display industry seeks large-area, high-resolution (8K+) organic light-emitting diode (OLED) panels.
• Current selective deposition methods (e.g., shadow masks) face limitations for large substrates requiring independently defined pixels.

Purpose of the Study:

• To adapt photolithography for precise OLED pixel patterning on large substrates.
• To demonstrate the feasibility of creating multi-color OLED pixels using photolithographic techniques.

Main Methods:

• Utilized a negative-tone highly fluorinated photoresist (PR) and fluorous solvents for patterning.
• Investigated potential damage to the hole-transporting layer (HTL) during developing and stripping processes.
• Employed a lift-off process to achieve pixel definition.

Main Results:

• No significant efficiency degradation was observed in devices processed with photolithography.
• Device efficiency after lift-off reached 72% of the reference device, with stable operating voltage.
• Successfully fabricated two-color OLED pixel arrays and demonstrated patterning of 15 μm green pixels.

Conclusions:

• Photolithography is a viable technique for producing high-resolution large OLED displays.
• The developed method is compatible with OLED fabrication, preserving device efficiency.
• This approach offers a promising solution for next-generation display manufacturing.