Design of Efficient Benzosilole Derivatives for Tuning High-Performance HLCT OLEDs

Area of Science:

• Organic electronics
• Materials science
• Photophysics

Background:

• Hybridized local and charge-transfer (HLCT) materials offer tunable properties for organic light-emitting diodes (OLEDs).
• Previous silole-based HLCT materials achieved 9.1% external quantum efficiency (EQE) but suffered from low photoluminescence quantum yields (PLQYs).
• Molecular design strategies are crucial for enhancing EQE and PLQY in OLED applications.

Purpose of the Study:

• To design and synthesize novel HLCT materials with improved photophysical properties for OLEDs.
• To investigate the effect of a more rigid benzosilole core on HLCT material performance.
• To achieve higher external quantum efficiency (EQE) and photoluminescence quantum yields (PLQYs) in OLED devices.

Main Methods:

• Synthesized benzosilole derivatives incorporating carbazole (Cz) or 9,9-dimethyl-9,10-dihydroacridine (Ac) as donors and triazine (TRZ) as acceptors.
• Fabricated OLED devices using the synthesized DCz-BS-TRZ and DAc-BS-TRZ materials.
• Characterized the photophysical properties, including PLQY, and device performance, focusing on EQE and efficiency roll-off.

Main Results:

• The benzosilole core led to higher PLQYs for both CT-like (DCz-BS-TRZ) and quasi-equivalent (DAc-BS-TRZ) HLCT molecules.
• The DCz-BS-TRZ based OLED device demonstrated a maximum EQE of 13%.
• This 13% EQE represents the highest efficiency reported for silole-based OLEDs.

Conclusions:

• A rigid benzosilole structure is a promising strategy for developing high-performance HLCT materials for OLEDs.
• The DCz-BS-TRZ material exhibits excellent potential for achieving high EQE in OLED applications.
• This work sets a new benchmark for EQE in silole-based OLED technology.