High-Performance Flexible Near-Infrared Organic Light-Emitting Diodes with a Heterogeneous Alloy Semitransparent...

Area of Science:

• Materials Science
• Optoelectronics
• Nanotechnology

Background:

• Flexible near-infrared (NIR) organic light-emitting diodes (OLEDs) suffer from low efficiency due to low photoluminescence quantum yields (PLQYs) in NIR emitters.
• Conventional flexible electrodes hinder the balance between microcavity-enhanced PLQY and light outcoupling efficiency (OCE) in OLEDs.

Purpose of the Study:

• To develop a novel micro-structured electrode for flexible NIR-OLEDs that enhances both PLQY and OCE.
• To overcome the limitations of conventional electrodes in balancing optical and electrical properties.

Main Methods:

• Fabrication of a micro-structured magnesium-bismuth (Mg-Bi) alloy electrode with broadband transmittance and conductivity.
• Integration of the Mg-Bi electrode with a capping layer into a flexible NIR-OLED device architecture.
• Characterization of optical properties, including transmittance, PLQY, and OCE, and device performance metrics.

Main Results:

• The Mg-Bi alloy electrode demonstrated 40% broadband transmittance (400-1600 nm) and high conductivity (29.3 Ω ◻^-1).
• The optimized device achieved 42.3% light outcoupling efficiency (OCE) and a 71.8% photoluminescence quantum yield (PLQY) for a 704 nm NIR emitter.
• Record 24.3% external quantum efficiency (EQE) for flexible NIR-OLEDs was achieved.

Conclusions:

• The micro-structured Mg-Bi alloy electrode effectively enhances PLQY and OCE in flexible NIR-OLEDs.
• This approach offers a universal strategy for developing high-efficiency flexible NIR optoelectronic devices.
• The synergy between optical engineering and conductive microstructures is key to advancing NIR optoelectronics.