Constructing high-efficiency orange-red thermally activated delayed fluorescence emitters by three-dimension...

Area of Science:

• Materials Science
• Organic Chemistry
• Solid-State Physics

Background:

• Developing efficient solution-processable orange-red thermally activated delayed fluorescence (TADF) emitters is a significant challenge in organic electronics.
• Existing TADF emitters often suffer from concentration quenching and exciton annihilation, limiting device performance.

Purpose of the Study:

• To design and synthesize novel TADF emitters with high efficiency and stability.
• To investigate the impact of molecular architecture and excited state regulation on TADF properties.
• To provide a universal strategy for high-performance TADF emitter design.

Main Methods:

• Molecular design of emitters based on a trinaphtho[3,3,3]propellane (TNP) core functionalized with TADF units.
• Utilizing the unique hexagonal stacking of TNPs to control molecular packing and reduce intermolecular interactions.
• Engineering excited states to enhance spin-orbit coupling (SOC) for efficient radiative decay.

Main Results:

• A series of solution-processable orange-red TADF emitters were successfully synthesized.
• The TNP core architecture effectively minimized concentration quenching and triplet exciton annihilation.
• One emitter achieved high-efficiency orange-red emission at 604 nm with a high SOC value (0.862 cm⁻¹) and photoluminescence quantum yield (70.9%).
• Fabricated organic light-emitting diodes (OLEDs) demonstrated a maximum external quantum efficiency of 24.74%.

Conclusions:

• The study presents a universal strategy for designing high-performance TADF emitters by controlling molecular packing and excited state properties.
• The TNP core provides a robust platform for developing efficient TADF materials.
• This work advances the development of solution-processable TADF emitters for next-generation OLED displays and lighting.