n-Type Oxazine-Fused Higher-Acene Analogues With High Stability and High Charge Mobility

Area of Science:

• Organic Chemistry
• Materials Science
• Nanoscience

Background:

• Higher-acenes are desirable for their large structures but suffer from instability and poor solubility.
• Developing stable n-type higher-acene analogues is crucial for advanced electronic applications.
• Existing higher-acene analogues lack the stability and performance required for practical use.

Purpose of the Study:

• To synthesize novel, stable, and soluble higher-acene analogues with n-type semiconductor properties.
• To investigate the electronic and optical characteristics of these new compounds.
• To evaluate their performance in organic field-effect transistors (OFETs).

Main Methods:

• Synthesis of pentaphenotetraoxazines (PPTOs) using oxazine and benzene building blocks via a chemical solution method.
• Characterization of PPTOs' solubility, stability, lowest unoccupied molecular orbital (LUMO) levels, and optical bandgap.
• Fabrication and testing of solution-processed organic field-effect transistors (OFETs) using PPTOs.

Main Results:

• Synthesized PPTOs exhibit high solubility and ambient stability.
• PPTOs possess deep LUMO levels (< -4.1 eV), strong near-infrared (NIR) absorbance, and narrow optical bandgaps (< 1.4 eV).
• OFET devices demonstrated electron mobilities exceeding 0.1 cm² V⁻¹ s⁻¹, significantly outperforming previous analogues and homologous compounds.

Conclusions:

• Oxazine-fused higher-acene analogues (PPTOs) offer a promising route to stable, high-performance n-type organic semiconductors.
• The developed PPTOs show excellent electron mobility and stability in OFETs without encapsulation.
• This strategy holds potential for designing even larger and more complex acene-based systems for future electronic applications.