Unraveling Various Stacking Modes and Local Structures in Poly(triazine imide) Materials via Low-Dose Electron...

Area of Science:

• Materials Science
• Nanotechnology
• Chemistry

Background:

• Poly(triazine imide) (PTI) materials are layered graphitic carbon nitrides with tunable properties.
• Post-synthesis treatments can modify PTI properties, but their effect on local structure and stacking is unclear.

Purpose of the Study:

• To investigate the influence of post-synthesis treatments on PTI layer stacking and local structure.
• To utilize low-dose electron microscopy for high-resolution imaging of PTI materials.

Main Methods:

• Integrated differential phase-contrast scanning transmission electron microscopy (iDPC-STEM) with controlled electron doses.
• Density functional theory (DFT) calculations.

Main Results:

• Acid treatments transform AA'-stacking to AB- and ABC-stacking (newly identified).
• Cation replacement drives stacking changes, influenced by electrostatic interactions.
• iDPC-STEM revealed chlorine presence on pristine PTI surfaces and its absence after acid treatment, indicating ion migration during stacking transformation.

Conclusions:

• Low-dose iDPC-STEM provides critical insights into PTI structural modifications.
• Acid treatments induce significant changes in PTI stacking modes and ion distribution.
• Understanding these structural changes is key to tailoring PTI properties for specific applications.