Light extraction from electroluminescent devices using micro-rod array embedded within glass substrate

Area of Science:

• Optoelectronics
• Materials Science
• Nanotechnology

Background:

• Total internal reflection (TIR) in conventional electroluminescent devices limits light out-coupling efficiency.
• Trapped light energy is converted to heat, degrading device performance and lifespan.

Purpose of the Study:

• To enhance light out-coupling efficiency in organic light-emitting diodes (OLEDs).
• To mitigate performance degradation caused by heat buildup from trapped light.
• To maintain optimal electrical properties while improving light extraction.

Main Methods:

• Fabrication of a micro-rod array (MRA) structure using a femtosecond laser.
• Integration of the MRA structure into green, blue, and red OLED devices.
• Comparative analysis of light out-coupling efficiency and electrical properties between MRA devices and conventional devices.

Main Results:

• The MRA structure increased out-coupling efficiencies by factors of 1.9 (green), 1.7 (blue), and 1.82 (red) compared to conventional devices.
• The proposed method demonstrated compatibility with existing device fabrication processes.
• The technique is applicable to full-color electroluminescent devices.

Conclusions:

• Femtosecond laser-fabricated MRA structures are highly effective in enhancing light out-coupling efficiency in OLEDs.
• This approach offers a viable solution to overcome TIR limitations in electroluminescent devices.
• The method is scalable and compatible with industrial fabrication, paving the way for brighter and more efficient displays.