Pyrene-based Y-shaped solid-state blue emitters: synthesis, characterization, and photoluminescence

Area of Science:

• Organic Chemistry
• Materials Science
• Photophysics

Background:

• Developing efficient and stable blue emitters is crucial for organic light-emitting devices (OLEDs).
• Pyrene derivatives offer a versatile scaffold for designing optoelectronic materials.

Purpose of the Study:

• To synthesize and characterize novel pyrene-based Y-shaped blue emitters.
• To investigate the structure-property relationships influencing their photophysical and thermal characteristics.
• To evaluate their potential as blue emitters in OLED applications.

Main Methods:

• Suzuki cross-coupling reaction for synthesis.
• X-ray crystallography for structural analysis.
• UV/Vis absorption and fluorescence spectroscopy for photophysical characterization.
• Density Functional Theory (DFT) calculations.
• Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) for thermal stability assessment.

Main Results:

• Successfully synthesized a series of 7-tert-butyl-1,3-diarylpyrenes.
• X-ray analysis showed suppressed π-π stacking due to steric hindrance from the tert-butyl group.
• Compounds exhibited efficient intramolecular charge-transfer emissions with solvatochromism.
• All compounds displayed highly efficient blue emission and excellent quantum yields in the solid state.
• Compounds with cyano (CN) and aldehyde (CHO) groups showed high thermal stability.

Conclusions:

• The synthesized Y-shaped arylpyrenes are effective blue emitters with suppressed intermolecular interactions in the solid state.
• Their twisted structures and efficient intramolecular charge transfer contribute to excellent solid-state fluorescence.
• The thermally stable compounds with electron-withdrawing groups are promising candidates for blue OLEDs.