n-Type Azaacenes Containing B←N Units.

Area of Science:

• Organic electronics
• Materials science
• Supramolecular chemistry

Background:

• Acenes are organic semiconductors with potential applications in electronics.
• Developing stable and efficient n-type organic semiconductors remains a challenge.
• Tuning electronic properties of organic molecules is crucial for device performance.

Purpose of the Study:

• To introduce a novel strategy for designing n-type acenes.
• To synthesize and characterize new azaacenes incorporating boron-nitrogen coordination bonds (B←N).
• To investigate the impact of B←N units on the electronic structure and charge transport properties of acenes.

Main Methods:

• Synthesis of novel azaacene molecules containing two B←N units.
• Characterization of electronic structures, including LUMO delocalization and aromaticity.
• Fabrication and testing of organic field-effect transistors (OFETs) using the synthesized materials.

Main Results:

• Successful synthesis of two azaacenes with six/eight linearly annelated rings and B←N units.
• Observation of unique LUMOs delocalized over the acene skeletons and reduced aromaticity in adjacent rings.
• Demonstration of low-lying LUMO energy levels and high electron affinities, resulting in n-type character.
• Achieved unipolar n-type characteristics in a solution-processed OFET with an electron mobility of 0.21 cm² V⁻¹ s⁻¹.

Conclusions:

• The introduction of B←N coordination bonds is an effective strategy for designing n-type acenes.
• The synthesized azaacenes exhibit desirable electronic properties for n-type organic semiconductor applications.
• These findings open new avenues for developing high-performance organic electronic devices.